Alcohol and drug screening of occupational drivers for preventing injury

Alcohol and drug screening of occupational drivers for
preventing injury (Review)
Cashman CM, Ruotsalainen JH, Greiner BA, Beirne PV, Verbeek JH
This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library2009, Issue 2 Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
PLAIN LANGUAGE SUMMARY AUTHORS' CONCLUSIONS CHARACTERISTICS OF STUDIES CONTRIBUTIONS OF AUTHORS DIFFERENCES BETWEEN PROTOCOL AND REVIEW Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Alcohol and drug screening of occupational drivers for
preventing injury
Clodagh M Cashman1, Jani H Ruotsalainen2, Birgit A Greiner3, Paul V Beirne3, Jos H Verbeek2 1Research Department, Medical Council, Dublin, Ireland. 2Finnish Institute of Occupational Health, Center of Expertise for GoodPractices and Competence, Team of Knowledge Transfer in Occupational Health and Safety, Cochrane Occupational Health Field,Kuopio, Finland. 3Department of Epidemiology and Public Health, University College Cork, Cork, Ireland Contact address: Clodagh M Cashman, Research Department, Medical Council, Lynn House Lower Rathmines Road, Dublin, 6,Ireland. Editorial group: Cochrane Injuries Group.
Publication status and date: New, published in Issue 2, 2009.
Review content assessed as up-to-date: 31 May 2007.
Cashman CM, Ruotsalainen JH, Greiner BA, Beirne PV, Verbeek JH. Alcohol and drug screening of occu- pational drivers for preventing injury. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: CD006566. DOI:10.1002/14651858.CD006566.pub2.
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
A B S T R A C T
Workforce alcohol and drug testing is commonplace but its effect in reducing occupational injuries remains unclear.
To assess the effects of alcohol and drug screening of occupational drivers (operating a motorised vehicle) in preventing injury or work-related effects such as sickness absence related to injury.
We searched the following databases up to June 2007 (or up to the latest issue then available): MEDLINE, EMBASE, The CochraneLibrary, Cochrane Occupational Health Field's specialised register, DARE, PsychINFO, ERIC, ETOH, CISDOC, NIOSHTIC,TRANSPORT, Zetoc, Science Citation Index and Social Science Citation index and HSELINE. We also searched reference lists,relevant websites and conducted hand searching.
Randomised controlled trials (RCTs), cluster-randomised trials, controlled clinical trials, controlled before and after studies (more thanthree time points to be measured before and after the study) and interrupted time-series (ITS) studies that evaluated alcohol or drugscreening interventions for occupational drivers (compared to another intervention or no intervention) with an outcome measured asa reduction in injury or a proxy measure thereof.
Data collection and analysis
Two review authors independently extracted data and assessed study quality. We contacted authors of the included studies for furtherinformation.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Main results
We included two interrupted time-series studies conducted in the USA. One study was conducted in five large US transportationcompanies (N = 115,019) that carried passengers and/or cargo. Monthly injury rates were available from 1983 to 1999. In the studycompany, two interventions of interest were evaluated: mandatory random drug testing and mandatory random and for-cause alcoholtesting programmes. The third study focused only on mandatory random drug testing and was conducted on federal injury data thatcovered all truck drivers of interstate carriers.
We recalculated the results from raw data provided by the study authors. Following reanalysis, we found that in one study mandatoryrandom and for-cause alcohol testing was associated with a significant decrease in the level of injuries immediately following theintervention (-1.25 injuries/100 person years, 95% CI -2.29 to -0.21) but did not significantly affect the existing long-term downwardtrend (-0.28 injuries/100 person years/year, 95% CI -0.78 to 0.21).
Mandatory random drug testing was significantly associated with an immediate change in injury level following the intervention (1.26injuries/100 person years, 95% CI 0.36 to 2.16) in one study, and in the second study there was no significant effect (-1.36/injuries/100person years, 95% CI -1.69 to 0.41). In the long term, random drug testing was associated with a significant increase in the downwardtrend (-0.19 injuries/100 person years/year, 95% CI -0.30 to -0.07) in one study, the other study was also associated with a significantimprovement in the long-term downward trend (-0.83 fatal accidents/100 million vehicle miles/year, 95% CI -1.08 to -0.58).
There is insufficient evidence to advise for or against the use of drug and alcohol testing of occupational drivers for preventing injuriesas a sole, effective, long-term solution in the context of workplace culture, peer interaction and other local factors. Cluster-randomisedtrials are needed to better address the effects of interventions for injury prevention in this occupational setting.
Alcohol and drug screening for preventing injury among people whose job involves driving
Alcohol and drug abuse are serious public health problems worldwide. Workplace alcohol and drug testing is a common intervention,especially in developed nations, but it is costly and its use is controversial. This systematic review aimed to assess the effects of alcoholand drug screening among occupational drivers for preventing injury.
We conducted a systematic search of the literature on the effects of alcohol and drug screening among occupational drivers for preventinginjury. We then appraised the quality of the studies found and assessed their results. We found two time-series studies conducted inthe USA. One was conducted in five large transportation companies, and it examined the effects of two interventions of interest:implementation of legislation for mandatory random drug testing and mandatory random and for-cause alcohol testing. The otherstudy was conducted using national injury data.
There is limited evidence that in the long term mandatory drug-testing interventions can be more effective than no intervention inreducing injuries in occupational drivers. For mandatory alcohol testing there was evidence of an immediate effect only.
Given the widespread practice of alcohol and drug testing and the paucity of evaluation studies found, more evaluation studies areneeded. Interrupted time-series is a feasible study design for evaluating interventions that aim at preventing alcohol and drug relatedinjuries. However, time-series studies of higher quality and of long duration are needed to increase the level of evidence. A cluster-randomised trial would be the ideal study design to evaluate the effects of interventions for injury prevention in this occupationalsetting.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
B A C K G R O U N D
is entitled to expect the highest standards of safety and probity (While selective drug-free workplace Description of the condition
programmes have been associated with an industry specific pre-ventive effect, this tends to occur in the construction and service The misuse of alcohol and illicit drugs constitutes a major global sectors where two key factors are influential: background level of public health problem ). In recent years, the role of injury risk and prevalence of substance abuse in the workforce ( alcohol and drug intoxication in work-related injuries and work- related crashes has received increasing attention ;; In some safety-critical occupationsa single mistake could have disastrous consequences in terms of How the intervention might work
death, injury and impact on public confidence ;Results of some recent surveys of alcohol and drug Alcohol and drug testing may prevent workplace-related injuries use provide ample cause for concern. In the United States (US), by deterring the misuse of illicit substances among employees military personnel service members between the ages 18 and 25 thereby reducing risks to health and safety in the work environ- had a twice as high prevalence of heavy drinking in the previous ment. Other purported benefits of testing include: improved em- 30 days as civilians in the same age group ). In a ployee welfare, reduced risks to the production process, enhanced British Health community postal survey, there was a significant as- public confidence in the organisation and improved medical fitness sociation between illegal drug use and work-related traffic crashes thereby reducing healthcare costs ).
independent of other associated variables like alcohol, health is- A recent study of analyses within the construction industry indi- sues and prescription drug use ). However a study cated that companies with drug-testing programmes experienced a analysing annual reports from 1995-2000 published by the US 51% reduction in injury incident rates within two years of imple- Department of Transportation estimated that only less than one mentation (). In contrast to general prevalence data, crash in 1,000 per year was attributable to employee alcohol use ( with a substance misuse testing programme in place in the US Air ). For drugs the estimate was 4 to 7 crashes annually Force, the overall test positive rates for marijuana and cocaine were in 1,000 crashes very low ).
Any potential benefits of testing must be weighed against poten-tial harms which include: the fallibility of testing and the conse- Description of the intervention
quences associated with false positives (for example, when legallyavailable drugs produce a positive test for illicit substances) and Alcohol and drug testing involves the analysis of biological ma- false negatives (the failure to identify persons misusing alcohol or terial to detect these substances or their metabolites in the body.
illicit drugs); the initiation of legal proceedings against employers Testing may involve analysis of blood, urine, saliva, sweat, hair and for inappropriately dealing with performance issues or policing breath samples The timing of work-related test- the private behaviour of the workforce ; ing can take a variety of forms, including pre-employment testing, Other potential harms include damaged employer/em- random testing of employees and post-accident testing, reasonable ployee relations and reduced productivity, negative impacts on suspicion testing, follow-up and return-to-duty testing.
'health and safety' arising from underreporting of minor injuries Workforce drug and alcohol testing is extremely controversial and or 'near misses' for fear of triggering testing procedures, stigmati- there has been prolonged debate over the effectiveness, cost-effec- sation of those testing positive and the human resource implica- tiveness, ethics and legality of the practice In the tions for those who may have tested positive in 'pre-employment US an estimated 80% of the large employers currently use some screening' (; Furthermore, cost is- form of alcohol and/or drug testing of employees sues and ethical issues have been raised. A sound testing method ). All Federal government employees and all workers in indus- and test chain process is not standardised internationally.
tries regulated by the Federal government are included in manda-tory screening programmes Mandatory drug test-ing for safety-sensitive occupations was announced in 1988 by Why it is important to do this review
the United States Department of Transportation Industry (federallaw) and implemented in 1990 There is a relative Ongoing research, monitoring and analysis of the impact and de- paucity of research evidence on the nature and extent of workforce velopment of drug testing at work have recently been advocated ( drug and alcohol testing outside the US. Legislation and imple- Although there have been several reviews written mentation varies between and within countries. In Canada, the on this topic, no systematic synthesis has previously been carried United Kingdom and other European countries, workforce test- out of the evidence relating to the benefits and harms of alcohol ing has been primarily concentrated in safety and security critical and drug testing in a workforce that primarily operates vehicles ( industries and professions where it has been argued that the public Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
O B J E C T I V E S
test was designed to detect (alcohol, cannabinoids, cocaine, am-phetamines, opiates, benzodiazepines, phencyclidine or prescrip- To assess the effects of alcohol and drug screening of occupational tion drugs).
drivers (operating a motorised vehicle) in preventing injury (orwork-related effects such as sickness absence related to injury).
Types of outcome measures
We included the numbers of: Criteria for considering studies for this review
• fatal injuries • non-fatal injuries • incidents without injury (for example, near miss, loss of Types of studies
All randomised controlled trials (RCT), cluster-randomised trials,controlled clinical trials (CCT), controlled before and after studies (CBA) or interrupted time-series studies (ITS) (with more than Intermediary outcomes (that may lead to a reduction in injuries) three time points to be measured before and after the study) eval- and outcomes that measured the consequences of injuries. These uating the effects of alcohol or drug testing in reducing injuries.
• behaviour change (that is, participation in treatment Types of participants
programme, or evidence of quitting the substance) We included studies in which the participants were adults whose • knowledge change regarding alcohol and/or drug misuse occupation involved the operation of motorised vehicles for the within organisational culture or individuals at work, generated purpose of transporting persons or goods or services.
by an alcohol and/or drug testing programme The following specific categories of vehicle operator/driver were • attitude change (that is, within an organisation that may include labour relations, change in working culture or withinindividuals who are being studied before and after an alcohol and • Persons operating motorised vehicles in the course of drug screening programme is introduced including private commercial or public duty designed to carry passengers.
This included, but was not limited to, bus drivers (including • sickness absence from work related to injury - the change in drivers of school buses), train drivers, taxi drivers, drivers/pilots the average number of sick leave absences of aircraft or sea craft.
• penalty imposed - the change in the number of suspensions • Persons operating motorised vehicles designed to transport from duty or legal outcomes for example, change in the number goods or services. This included, but was not limited to, haulers/ of driving while intoxicated suspensions distributors, postal delivery workers, couriers and salesrepresentatives.
• Persons operating motorised vehicles during the course of Search methods for identification of studies
work that may not have been included under the abovecategories. This included, but was not limited to, drivers of We did not restrict the searches by publication status, date, lan- military vehicles, construction workers, farming workers, oil guage or country.
industry workers, mine/quarry workers and warehouse workers.
Types of interventions
We included studies where the intervention was any form of al- • MEDLINE (PubMed, 1950 to 28 May 2007) cohol and or drug testing administered to the types of partici- • EMBASE (1966 to 28 May 2007) pants listed above, with the intention of reducing work(er)-related • CENTRAL (to 29 May 2007) injuries. We aimed to categorise interventions according to the • Cochrane Injuries Group's specialised register (The timing and purported rationale for testing (pre-employment, ran- Cochrane Library Issue 2, 2007) dom, post-incident, reasonable suspicion, return to duty, fol ow- • Cochrane Occupational Health Field's specialised register up or post-rehabilitation) and according to the substance that the (The Cochrane Library Issue 2, 2007) Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
• DARE (The Cochrane Library Issue 2, 2007) • what biological sample was used for the test (e.g. breath, • Economic Evaluations (The Cochrane Library Issue 2, urine, blood, saliva, sweat, hair, nails); • how the test was carried out such as, on-site testing test • PsychINFO (1967 to 2007/02) (approved protocol, tamper proof seal, chain of custody) or • ERIC (1966 to 29 May 2007) laboratory confirmation (gas chromatography/mass • ETOH (1972 to 31 May 2007) • CISDOC/International Labour Organisation (ILO) (1987 • what substance was tested for such as alcohol, cannabinoids, cocaine, amphetamines, opiates, benzodiazepines, • NIOSH (1900 to 2006/12) phencyclidine, prescription drugs; • TRANSPORT (1972 to 25 May 2007) • duration of follow-up (RCT) or data collection in each • Zetoc (1993 to 1 June 2007) period (CBA, ITS); • Science Citation Index and Social Science Citation index • primary outcome measures: the change in number or injury (1986 to 28 May 2007) or incidents or deaths; • HSELINE national research register (1987 to 2006/12) • secondary outcome measures: the change in the average number of sick days, the change in numbers of penalties incurred The search strategy for each database is described in (for example, at work or by the legal system), change inbehaviour, knowledge or attitude change; Searching other resources
• cost: information about costs associated with implementing We contacted national and international agencies, and the authors the intervention and relation to outcome(s).
of relevant studies, to identify additional studies possibly eligible However, only two studies (one of which was reported in two for inclusion. In addition we hand searched the reference lists of papers) met our inclusion criteria and they included information studies screened for inclusion and searched the website of the US only on the schedule of data collection and on primary outcomes.
Department of Transportation (for eligible studies.
One article addressed costs.
We also hand searched all issues of Traffic Injury Prevention and Although we contacted the authors for clarification, we were un- Accident Analysis and Prevention up to June 2007. The date of able to obtain the relevant information about what samples or the last search was June 2007.
testing methods were used.
Assessment of risk of bias in included studies
Data collection and analysis
Two review authors (CC and JR) independently assessed themethodological quality of the included studies. The two reviewauthors independently rated the publications describing the in- Selection of studies
cluded studies with the quality criteria for interrupted time series The search strategies outlined above were carried out. Two review (ITS) study designs ). The two review authors then authors (CC and JR) undertook study selection where the authors worked together and performed the rating a second time. All dis- screened abstracts and titles for relevance before retrieving the full agreements were resolved by discussion and by jointly clarifying texts. Both independently assessed whether the studies found met the criteria used for assessment. In cases of persistent disagreement, the pre-defined inclusion criteria. We obtained the full text of a third author (JV) was involved in the decision.
all potentially relevant records and obtained further information The quality criteria for interrupted time series (ITS) study designs from authors when a paper contained insufficient information for consists of an appraisal of studies in eight domains reaching a decision on eligibility.
• Had the intervention occurred independently of other changes over time? Data extraction and management
• Was the intervention unlikely to affect data collection? Two review authors (CC and JR) independently extracted data • Was the primary outcome assessed blindly or measured from the included studies regarding the country where the study was conducted, the type of study design used, characteristics of • Was the primary outcome reliable or measured objectively? the study participants (as per study inclusion criteria) and types • Did the composition of the data-set at each point in time of interventions and outcomes. A third author (JV) resolved any cover at least 80% of the total number of participants in the We intended to extract the following information about specific • Was the shape of the intervention effect specified a priori? components of testing methods: • Was a rationale for the number and spacing of data points Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
• Was the study analysed appropriately using time-series the first intervention time point and that predicted by the pre- intervention time trend.
No pooling of data across studies was carried out because one study We did not use the tool to derive a summary score of quality; used measured data and the other used federal records that didn't instead we report how the study performed within each domain.
show how many drivers the intervention affected.
We used a rating system, based on the Levels of Evidence ), to summarise the strength of scientific evidence of We considered addressing publication bias by means of a funnel the effects of the intervention. The rating system was based on plot and checking for asymmetry. However there were less than both the quality and the outcome of the studies as follows: the required minimum of five studies available to be put in the I. Strong evidence - consistent findings in multiple high quality funnel plot.
RCTs or CCTs;II. Moderate evidence - consistent findings in multiple low qualityRCTS, CBAs, ITS and/or one high quality RCT; Measurement of intervention effect
III. Limited evidence - one low quality RCT or one CBA study or Outcomes reported in were recalculated as number of injuries per 100 person years during a given time period. The IV. Conflicting evidence - inconsistent findings in multiple trials; scarcity of data reported in prevented us from recal- V. No evidence - no trials.
culating the reported numbers of fatal accidents per 100 millionvehicle miles travelled into anything else. The results of the in- Subgroup analysis and investigation of heterogeneity
cluded studies were reanalysed as to both the change in level andchange in trend after the intervention as previously described ( There were insufficient data to perform a subgroup analysis ac- cording to the type of intervention (for example, pre-employmenttesting, random testing, post-incident testing).
Dealing with missing data
We contacted the study authors for any missing data. Additional We considered conducting sensitivity analyses to determine the information regarding study details and statistical data was sought impact of excluding studies with lower methodological quality.
and received from the authors. The results of this review are based However, only two studies met the inclusion criteria for this review.
on calculations performed using these data.
Methods for future updates
The review authors intend to perform a new search for eligible For time-series studies, data from the original papers were reanal- studies every two years and to update the review accordingly.
ysed according to the recommended methods for analysis of in-terrupted time-series (ITS) designs for inclusion in systematic re-views These methods utilise a segmented time-series regression analysis to estimate the effect of an interventionwhile taking into account secular time trends and any autocor- relation between individual observations. For each study, a firstorder autoregressive time-series model was fit to the data using amodification of the parameterization of . Details of Description of studies
the mode specification are as follows: Y= ß0+ ß1time+ ß2 (time-p) I(time > p) +ß3 I(time > p)+ E, E N(0, s2)For time =1,.,T, where p is the time of the start of the intervention,I (time > =p) is a function which takes the value 1 if time is p or Results of the search
later and zero otherwise, and where the errors E are assumed to Approximately 6000 potentially relevant publications were identi- follow a first-order autoregressive process (AR1). The parameters fied and screened for retrieval. Following assessment on the basis of ß have the following interpretation: title and abstract only 19 full text article publications were consid- ß1 is the pre-intervention slope.
ered for inclusion in this review, and were scrutinised further with ß2 is the difference between post and pre-intervention slopes.
regard to our inclusion and exclusion criteria. Sixteen articles were ß3 is the change in level at the beginning of the intervention period, meaning that it is the difference between the observed level at Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
;(see'Characteristics of excluded studies' table). Therefore, only twostudies and published as two articles)met the inclusion criteria and were included in this review (see'Characteristics of Included Studies' table and ).
Alcohol and drug screening of occupational drivers for preventing injury (Review)
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Figure 1. Trial flow.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
were outlined in the federal testing regulations to be interpreted by management of the employing organisation. The PeerCare in-tervention that did not fulfil our inclusion criteria was introduced Two studies from the United States, of which one was reported in in 1987. It was a union-management partnership and training ac- two publications, were included in this review and tivity to recognize and intervene with problem (impaired) work- ers on-the-job, and to change attitudes to substance use in the Design of the study workplace. In addition, in 1995 there was a safety restructuring is an evaluation of a workplace peer-focused substance procedure that affected one of the study companies.
abuse prevention and early intervention program (titled PeerCare) Types of outcome measures evaluated against the background of federally mandated random The primary outcome measure in was the injury rate drug and alcohol testing in an interrupted time-series design from per 100,000 employee-hours. The secondary outcomes were the 1983 to 1996. Because we were given access to the raw data we costs of both program implementation and of occupational in- could focus our reanalysis on the testing interventions instead of juries. In the primary outcome measure was the rate of the primary substance abuse prevention intervention. This voided large truck fatal accidents per 100 million vehicle miles travelled.
the reported intervention versus control setup and made all study A large truck was defined as weighing over 10,000 pounds gross companies part of the intervention group. evaluated vehicle weight, including single unit trucks and truck tractors.
the effects of the PeerCare and testing interventions, and measuredreportable injuries only, whereas another paper that used the same data (Miller 2007) measured both reportable and minor injuriesand estimated the cost effectiveness of the PeerCare and testing The main reasons for excluding the remaining sixteen identified studies were as follows (see table of ' is an evaluation of federally mandated random drug testing on fatal truck accidents in an interrupted time-series design (a) Inappropriate study design (i.e. not a randomised controlled from 1983 to 1997. The data were obtained from the Fatality trial (RCT), cluster-randomised trial, controlled clinical trial Analysis Reporting System database which is maintained by the (CCT), controlled before and after study (CBA) or interrupted National Highway Traffic Safety Administration.
time series studies (ITS) ; Participants and duration of study In a retrospective analysis was conducted using cross- sectional time-series data to examine the association between oc- (b) Study did not evaluate the effects of alcohol or drug testing cupational injury rate and (1) federally mandated drug testing and in reducing injuries ; ; (2) federally mandated alcohol testing. The study duration was 13 years, from 1983 until 1996. The study population consisted of approximately 115,019 employees in five large interstate transport Risk of bias in included studies
companies that carried passengers and/or cargo in the USA. Thenumber of occupational injuries reported to the Federal govern- met four of the quality criteria recommended for ment between January 1983 and June 1996, that were calculated as interrupted time-series studies ): injuries per 100,000 employee-hours, was tabulated monthly for The intervention was unlikely to affect data collection. As the main the five companies (study and controls). Injuries were reportable outcome was routinely collected data on injuries to be reported to to the Federal government if they resulted in (1) death or medical the federal regulatory agency, it is unlikely that the introduction treatment and/or (2) restricted or lost workdays. In Miller 2007, of drug and alcohol testing impacted on the way the data was col- injury data was available until 1999 and included reportable as lected. The authors indicated that they merged individual records well as not-reportable injuries. These were generally minor injuries with personnel files with negligible problems.
that were treated by a non-health professional and did not result The primary outcome was assessed blindly or measured objectively.
in lost work days.
The injury figures were good objective measures of medium to reports that the number of active truck drivers (i.e.
serious injuries as they included only those injuries to be reported number of participants exposed to the intervention) is not actually to the federal regulatory agency. Reportable injuries were defined known with a sufficient degree of accuracy. The study duration by clear criteria (injuries that result in death, medical treatment was 14 years, from 1984 to 1997.
and/or restricted or lost work days).
Types of interventions The primary outcome was reliable or measured objectively.
In the USA, federally mandated random drug testing for safety- The composition of the data set at each point in time covered at sensitive occupations in the transportation industry commenced least 80% of the total number of events in the study. As monthly on January 1st 1990 and random and for-cause alcohol testing on official injury statistics were used we assume that these covered August 15th 1994. Biological sampling and the quality of testing close to 100% of all events that happened in the particular month.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
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did not meet the remaining four criteria: official injuries statistics were used we assume that these covered The shape of the intervention effect was not specified a priori. The close to 100% of all events that happened in the particular month.
study lacked specific hypotheses. Neither the expected effect of the did not meet the remaining four criteria.
random alcohol and drug testing nor the effect of the Peer Care The shape of the intervention effect was not specified a priori. programme were specified in advance.
The study lacked specific hypotheses. The expected effect of the The intervention had not occurred independently of other changes random drug testing programme was not specified in advance.
over time. The introduction of federally mandated drug testing No rationale for the number and spacing of data points was de- (1990) followed by alcohol testing (1994) overlapped with the scribed. The period covered was probably long enough to reveal Peer Care intervention (1987) making it difficult to differentiate both immediate and long-term post-intervention effects on in- between the effects of the interventions. The workplace culture of the study companies is also likely to have changed in the pre- Most likely the intervention did not occur independently of other intervention period when the US government changed Federal changes over time because it is not known who were actually af- employment culture in 1986 by requiring employees to refrain fected by the intervention and to what degree. If one assumes that from the use of illegal drugs. In addition, safety restructuring in the data represent all large interstate truck drivers then one can one of the study companies in 1995 also overlapped with the drug also assume that these individuals were also subjected to various and alcohol testing.
limitations, rules, etc. No other influences apart from drug testing No rationale for the number and spacing of data points was de- were considered in the study.
scribed. However, the spacing of data points was pre-set by the The study was analyzed appropriately as to the immediate effect monthly injury data reporting and can be considered as sensitive but did not take into account the possibility of auto-correlation of enough to show changes in injuries over time due to the interven- the data. The change in fatality rate per 100 million vehicle miles tions. The period covered was probably long enough to reveal both travelled was modelled by linear regression over the years 1984 to immediate and long-term post-intervention effects on injuries.
1989. These were then extrapolated over the following years. In The main emphasis of the study was on evaluating the effect of the other words, the authors compared the scores following the in- Peer Care programme rather than random alcohol or drug testing.
troduction of the intervention to those that would have been ex- Therefore the applied analyses were not relevant for isolating the pected based on the scores from before the intervention instead of effects of random drug and alcohol testing from the effects of the comparing pre-intervention scores with post-intervention scores.
Peer Care programme.
There was no analysis of the long-term effect.
Weaknesses in the study are indicated by a lack of data on post-accident drug and alcohol tests from the period prior to the work- Effects of interventions
place intervention. Separate analysis of subgroups was not possi-ble.
also met four of the quality criteria recommended for Mandatory alcohol testing versus no alcohol testing
interrupted time-series studies (The intervention was unlikely to affect data collection. As the main Immediate effect on injury level
outcome was routinely collected data on injuries to be reported to In , mandatory random and for-cause alcohol testing the federal regulatory agency it is unlikely that the introduction was associated with a decrease in the level of injuries immediately of drug testing impacted on the way the data was collected.
following the intervention (-1.25 injuries/100 person years, 95% The primary outcome was assessed blindly or measured objectively.
CI -2.29 to -0.21) The accident rate figures were good objective measures. Reportableinjuries were defined by clear criteria (injuries that result in death).
Long-term change in time-trend of injury level
The primary outcome was reliable or measured objectively.
In , there was no significant change in the already The composition of the data set at each point in time did cover at downward trend (-0.28 injuries/100 person years/year, 95% CI - least 80% of the total number of events in the study. As monthly 0.78 to 0.21) (see ).
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Figure 2. Injury rate in .
Mandatory drug testing versus no drug testing
Immediate effect on injury level
In mandatory random drug testing was associatedwith a statistically significant increase in injury level followingthe intervention (1.26 injuries/100 person years, 95% CI 0.36 to2.16). In there was no immediate statistically signif-icant effect for mandatory random drug testing (-1.36/injuries/100 person years, 95% CI -1.69 to 0.41) (see ).
Alcohol and drug screening of occupational drivers for preventing injury (Review)
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Figure 3. Rate of large truck fatal accidents in
We found no randomised trials of the effects of drug or alcohol Long-term change in time-trend of injury level
testing of drivers for reducing injuries. The two included studies In , the intervention was associated with a significant were interrupted time-series studies conducted in the USA. These decline of the yearly injury rate additional to the already downward studies provide limited evidence that mandatory random drug trend over time (-0.19 injuries/100 person years/year, 95% CI - testing can decrease injuries in the long term although the results 0.30 to -0.07). Also in the intervention was associated in the short term were contradictory. In one study, the effect size with a significant further improvement of the downward trend (- of the continuous drop of 0.19 injuries per 100 person years was 0.83 fatal accidents/100 million vehicle miles/year, 95% CI -1.08 small although the estimate can be considered as fairly precise with 95% confidence intervals ranging from 0.30 to 0.07. Anotherstudy found that mandatory random drug testing can increase the downward trend of the rate of fatal accidents by -0.83 fatalaccidents per 100 million vehicle miles travelled per year.
Miller 2007 (under reported the costs of the drugand alcohol testing interventions and the estimated costs ($US) ofthe avoided injuries at one transportation company. The drug andalcohol testing interventions cost altogether $35 per employee and The immediate drop in level of injuries (1.25 injuries/100 per- together with the peer worker mediated substance abuse program, son years) after the implementation of mandatory random and which cost another $35 per employee, avoided an estimated $1850 for-cause alcohol testing in the study can be judged in employer injury costs per employee in 1999, corresponding to as substantial although fairly imprecise. No change in the long- a benefit-cost ratio of 1:26.
term slope - additional to the already downward trend - could beshown following this intervention. This could be due to the lim-ited number of measurement points after the implementation ofalcohol testing in 1994, thereby compromising statistical power.
D I S C U S S I O N
The change in the long term slope following the implementation Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
of random drug testing in can only be seen as an Comparison with other reviews
approximation of the effect of the intervention because the size of We found no previous systematic or narrative reviews of the effects the population represented by this data is not known.
of drug or alcohol testing to reduce injuries specifically in drivers.
The study also assessed the effects of a peer-worker The review by about the effects of drug testing to mediated workplace substance abuse programme (PeerCare) on decrease injuries in nonspecific workplaces concluded that: ".the the background of federally mandated drug and alcohol testing.
published evidence for effects such as reduced injury or accident Because of the overlap of these three interventions the independent rates lacks scientific detail". In another systematic review about effects of the testing interventions are difficult to differentiate.
injury prevention in a different occupational setting, the construc-tion industry ), an intervention aiming at According to the same study (publication Miller 2007) drug and a drug-free workplace evaluated with an interrupted time-series alcohol testing interventions may also be cost-effective, at least design in a large company was shown to be effective in reducing in the US. However, the figures are based on overall company the level and the trend of injuries over time. The interrupted time- costs that, according to the authors, did not include some relevant series design therefore seems to be feasible in evaluating interven- costs like those of a pre-existing employee assistance program. The tions that aim to prevent injuries in the workplace. A standardised authors also do not describe the testing regimes in sufficient detail approach to analysis and reporting is needed to be able to compare to allow comparisons with the costs expected in the healthcare and possibly synthesize data across studies.
systems of other countries. For this reason we did not try to adjustthe figures for inflation or currency. Since we did not include in oursystematic search strategy items or specialist databases addressingeconomic evaluation it is possible that we may have overlooked studies and data other than those conducted alongside effectivenessstudies. The two included studies were both conducted in the USA Implications for practice
and so it is unclear how the results might apply to Europe or tolow and middle income countries.
There is insufficient evidence to advise for or against the use ofdrug and alcohol testing of occupational drivers for preventing The excluded studies either used ITS study designs that did not injuries as a sole, effective, long-term solution in the context of satisfy our inclusion criteria (i.e. less than three time points mea- workplace culture, peer interaction and other local factors.
sured before and after the study), or they did not relate substancetesting with number of injuries.
Implications for research
A strong aspect of our time-series analysis is that it adjusted for Given the widespread practice of alcohol and drug testing and secular and other cyclical changes in the auto-regressive time-series the paucity of evaluation studies found, more evaluation studies model. This is especially pertinent with this review as the past are needed. Interrupted time-series is a feasible study design for fifty years have shown a rather steady downward trend in injuries.
evaluating interventions that aim at preventing alcohol and drug Nonetheless, a clear drawback of the time-series design is that it is related injuries. However, time-series studies of higher quality and susceptible to bias as introduced by co-interventions (interventions of sufficient duration are needed to increase the level of evidence.
that are introduced concurrently), as well as the determination of A cluster-randomised trial would be the ideal study design to eval- the point in time where the intervention is introduced and the type uate the effects of interventions for injury prevention in this oc- of effect the intervention can have over time. Our recalculations of cupational setting.
the results consider only one intervention at a time by comparingall data points preceding the intervention to those following it.
It was not possible to assess the extent to which publication biasmay have been present due to the small number of included studies.
We attempted to reduce the likelihood of language bias by not Merja Jauhiainen from the Cochrane Occupational Health Field having language restrictions in the systematic search strategy.
for conducting most of the database searches. Karen Blackhall Cluster-randomised trials are needed to better address the effects from the Cochrane Injuries Group for assistance with database of interventions for injury prevention in this occupational setting.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
R E F E R E N C E S
References to studies included in this review
Spicer 2003 {published data only}
Spicer RS, Miller TR, Smith GS. Worker substance use, workplace Spicer 2005 {published data only}
problems and the risk of occupational injury: a matched case- Miller TR, Zaloshnja E, Spicer RS. Effectiveness and benefit-cost of control study. Journal of studies on alcohol 2003;64(4):570–8.
peer-based workplace substance abuse prevention. Accident; analysis
and prevention 2007;39(3):565–73.
Taggart 1989 {published data only}
∗ Spicer RS, Miller TR. Impact of a workplace peer-focused Taggart RW. Results of the drug testing program at Southern Pacific substance abuse prevention and early intervention program.
Railroad. NIDA research monograph 1989;91:97–108.
Alcoholism, clinical and experimental research 2005;29(4):609–11.
Wickizer 2004 {published data only}
Swena 1999 {published data only}
Wickizer T, Kopjar B, Franklin G, Joesch J. Do drug-free workplace Swena DD. Effect of Random Drug Screening on Fatal programs prevent occupational injuries? Evidence from Commercial Truck Accident Rates. International Journal of Drug Washington State. Health Services Research 2004;39(1):91–110.
Zaloshnja 2006 {published data only}
References to studies excluded from this review
Zaloshnja E, Miller T. The employer costs of motor vehicle crashes.
International journal of injury control and safety promotion 2006;13
Beirness 2004 {published data only}
Beirness DJ, Marques PR. Alcohol ignition interlock programs.
Zaloshnja 2007 {published data only}
Traffic injury prevention 2004;5(3):299–308.
Zaloshnja E, Miller TR, Hendrie D, Galvin D. Employer costs of Gerber 2001 {published data only}
alcohol-involved injuries. American journal of industrial medicine Gerber JK, Yacoubian GS. An assessment of drug testing within the construction industry. Journal of drug education 2002;32(1):53–68.
Zwerling 1990 {published data only}
Jacobson 2003 {published data only}
Zwerling, C. Ryan, J. Orav, E. J. The efficacy of preemployment Jacobson M. Drug testing in the trucking industry: the effect on drug screening for marijuana and cocaine in predicting highway safety. Journal of Law and Economics 2003;XLVI:131–56.
employment outcome. Journal of the American Medical Association. Kraus 2001 {published data only}
Kraus JF. The effects of certain drug-testing programs on injury Zwerling 1992 {published data only}
reduction in the workplace: an evidence-based review. International Zwerling C, Ryan J, Orav EJ. Costs and benefits of preemployment journal of occupational medicine and environmental health 2001;7
drug screening. Journal of the American Medical Association 1992; Lindseth 2001 {published data only}
Lindseth PD, Vacek JJ, Lindseth GN. Urinalysis drug testing within a civilian pilot training program: did attitudes changeduring the 1990's?. Aviation, Space and Environmental Medicine Cunradi 2005
Cunradi CB, Ragland DR, Greiner B, Klein M, Fisher JM.
Attributable risk of alcohol and other drugs for crashes in the transit Mumenthaler 2003 {published data only}
industry. Injury Prevention 2005;11(6):378–82.
Mumenthaler MS, Yesavage JA, Taylor JL, O'Hara R, Friedman L,Lee H, Kraemer HC. Psychoactive drugs and pilot performance: a Downs 1998
comparison of nicotine, donepezil, and alcohol effects.
Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and Peek-Asa 1999 {published data only}
non-randomised studies of health care interventions. Journal of Peek-Asa C. The effect of random alcohol screening in reducing epidemiology and community health 1998;52(6):377–84.
motor vehicle crash injuries. American journal of preventive medicine [PUBMED: 9764259] Seijts 2005 {published data only}
Fernandez WG, Hartman R, Olshaker J. Brief interventions to Seijts, G.H, O'Farrell, G. Urine Collection Jars Versus Video reduce harmful alcohol use among military personnel: lessons Games: Perceptions of Three Stakeholder Groups toward Drug learned from the civilian experience. Military Medicine 2006;171
Testing and Impairment Testing Programs. Journal of Drug Issues Francis 2003
Snowden 2007 {published data only}
Francis P, Hanley N, Wray D. A literature review on the Snowden C, Miller TR, Waehrer GM, Spicer RS. Random alcohol international state of knowledge of drug testing at work with testing reduced alcohol-involved fatal crashes of drivers of large particular reference to the US on behalf of the Independent Inquiry trucks. Journal of Studies on Alcohol and Drugs 2007;68(5):634–40.
on Drug Testing at Work. University of Northumbria 2003.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
French 2004
at a large manufacturing firm. American Journal of Drug and Alcohol French MT, Roebuck MC, Kebreau Alexandre P. To test or not to test: do workplace drug testing programs discourage employee drug Ramsay 2004
use?. Social Science Research 2004;33:45–63.
Ramsay C, Matowe L, Grilli R, Grimshaw J, Thomas R.
Gerber 2002
Interrupted times series designs in health technology assessment: Gerber JK, Yacoubian GS Jr. An assessment of drug testing within lessons from two systematic reviews of behavior change strategies.
the construction industry. Journal of Drug Education 2002;1:53–68.
International Journal of Technology Assessment in Health Care 2003;
19(04):613–23.
Grayson 2004
Grayson JK, Gibson RL, Shanklin SL, Neuhauser KM, McGhee.
Robinson KA, Dickersin K. Development of a highly sensitive Trends in Positive Drug Tests, United States Air Force, Fiscal Years search strategy for the retrieval of reports of controlled trials using 1997-1999. Military Medicine 2004;169(7):499–504.
PubMed. International Journal Epidemiology 2002;31(1):150–3.
Higgins 2005
Rodgers 2004
Higgins JPT, Green S editors. Cochrane Handbook for Systematic Rodgers A, Ezzati M, Vander Hoorn S, Lopez AD, Lin RB, Murray Reviews of Interventions 4.2.5 [updated May 2005] issue 3. The CJ, Comparative Risk Assessment Collaborating Group.
Cochrane Library. Chichester, UK: John Wiley & Sons, Ltd, 2005.
Distribution of major health risks: findings from the Global Hope 2005
Burden of Disease study. Public Library of Science Medicine. Epub Hope A, Gill A, Costello G, Sheehan J, Brazil E, Reid V. Alcohol and injuries in the accident and emergency department - a national perspective. Dublin: Department of Health and Children, 2005.
Rothstein M. Workplace drug testing: a case study in themisapplication of technology. Harvard Journal of Law and IIDTW 2004
Independent Inquiry into Drug Testing at Work. Drug testing inthe workplace: The report of the Independent Inquiry into Drug Smith 2004
Testing at Work. Joseph Rowntree Foundation 2004.
Smith A, Wadsworth E, Moss S, Simpson S. The scale and impactof illegal drug use by workers. Health and Safety Executive, Levine 2004
London 2004.
Levine MR, Rennie WP. Pre-employment urine drug testing of hospital employees: future questions and review of current Spiehler V. Drug screening in the USA. Bandolier 1994; Vol. 5.
literature. Occupational and Environmental Medicine 2004;61:
318–24.
van der Molen 2007
van der Molen HF, Lehtola MM, Lappalainen J, Hoonakker PL, Messer 1996
Hsiao H, Haslam R, et al.Interventions for preventing injuries in Messer, D. An empirical evaluation of the legal assumptions the construction industry. Cochrane Database of Systematic Reviews underlying workplace-based drug and alcohol testing: results from 2007, Issue 4. [DOI: 10.1002/14651858.CD006251.pub2] a comparison of random and non-random testing programs at a van Tulder 2003
large transportation agency. UMI Dissertation Services, Ann Arbor, van Tulder M, Furlan A, Bombardier C, Bouter L, Editorial Board Michigan;. UMI Company, Ann Arbor, MI, 1996.
of the Cochrane Collaboration Back Review Group. Updated method guidelines for systematic reviews in the cochrane Ozminkowski RJ, Mark TL, Goetzel RZ, Blank D, Walsh JM, collaboration back review group. Spine 2003; Vol. 28, issue 12: Cangianelli L. Relationships between urinalysis testing for substance use, medical expenditures, and the occurrence of injuries ∗ Indicates the major publication for the study Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Characteristics of included studies [ordered by study ID]
Spicer 2005
Time-series study with control.
115,019 employees in five large interstate transport companies that carried passengers and/or cargo.
1986 Change in employment requirements for federal employees.
1987 Peer-worker mediated substance abuse program (Peercare) introduced.
1990 Federal mandate for random drug testing.
1994 Federal mandate for random and for-cause alcohol testing introduced.
1995 Safety restructuring in one study company.
Injuries per 100,000 employee hours.
Same study as Miller 2007 but with slightly different variables.
Risk of bias
Allocation concealment? Swena 1999
Retrospective time-series study on large truck drivers' fatal accident data obtained from the Federal High-way Administration.
The number of active truck drivers that were subjected to the intervention is not known.
Random drug testing.
Fatality rate per 100 million vehicle miles travelled.
Risk of bias
Allocation concealment? Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Characteristics of excluded studies [ordered by study ID]
Review about the effectiveness of alcohol ignition interlock programs.
Prevalence study.
Prevalence study.
Review about the effectiveness of drug testing interventions in mixed occupational settings.
No control group.
Comparison of specific psychoactive drugs on pilot performance; Intermediate measure used as outcome (flightsimulator tests).
Review about the effectiveness of randomly stopping and breath testing drivers to deter from drinking anddriving.
Review of perceptions toward testing.
Case - control study.
Prevalence study.
Interrupted time-series study without three measurements before the introduction of the intervention.
Quasi- experimental; not specific for drug/alcohol intervention.
Cost estimate study.
Cost estimate study.
Cost estimate study.
Cost estimate study.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
This review has no analyses.
A P P E N D I C E S
Appendix 1. Search strategy
The search string for randomised controlled trials was based on .
PubMed search strategy (to 28.5.2007)
#1 drug* OR cannabi* OR opia* OR cocaine OR amphetamine* OR phencyclidine* OR benzodiazepine* OR alcohol OR medication*
OR prescription* OR medicament* OR pharmaceutical* OR sedative* OR intoxicat* OR drunk* OR drink* OR "substance abuse"
OR marijuana OR DUI OR DWI
#2 (lorry OR lorries OR truck OR trucks OR bus OR buses OR van OR vans OR tram OR trams OR train OR trains OR railroad
OR railroads OR taxi OR taxis) AND (driver*)
#3 (lorry OR lorries OR truck OR trucks OR bus OR buses OR van OR vans OR tram OR trams OR train OR trains OR railroad
OR railroads OR taxi OR taxis) AND (driving)
#4 captain OR seafarer* OR sailor* OR seaman
#5 pilot* AND (airline* OR aviation OR airplane* OR aircraft OR aeroplane* OR airship*)
#6 pilots
#7 commercial* AND (drive* OR driving)
#8 (driver* OR driving) AND (worker* OR working* OR occupation*)
#9 #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8
#10 #1 AND #9
#11 randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized controlled trials [mh] OR random allocation
[mh] OR double-blind method [mh] OR single-blind method [mh] OR clinical trial [pt] OR clinical trials [mh]) OR ("clinical trial"
[tw]) OR ((singl* [tw] OR doubl* [tw] OR trebl* [tw] OR tripl* [tw]) AND (mask* [tw] OR blind* [tw])) OR (placebos [mh] OR
placebo* [tw] OR random* [tw] OR research design [mh:noexp] OR comparative study OR evaluation studies [mh] OR follow-up
studies [mh] OR prospective studies [mh]) NOT (animals [mh] NOT human [mh])
#12 (effect* [tw] OR control* [tw] OR evaluation* [tw] OR program* [tw])
#13 #11 OR #12
#14 #10 and #13
EMBASE (to 28.5.2007)
#1
randomized controlled trial/exp OR randomization/exp OR clinical trial/exp OR clinical trials/exp OR controlled study/exp OR double
blind procedure/exp OR single blind procedure/exp OR ((singl* OR doubl* OR trrbl* OR tripl*) AND (mask* OR blind*)) OR
placebo*OR comparative study/exp OR research design/exp OR evaluation study OR evaluation studies/exp OR follow up/exp OR
prospective study/exp
OR effect* OR control* OR evaluation/exp OR program*
#2
drug/exp OR drugs/exp OR cannabi* OR opia* OR cocaine* OR amphetamine* OR phencyclidine* OR benzodiapine* OR alcohol/
exp OR medication* OR presciption* OR medicament* OR pharmaceutical* OR sedative* OR intoxicat* OR drunk* OR drink* OR
"substance abuse"/exp OR marijuana/exp OR dui OR dwi
#3
(lorry OR lorries OR truck OR trucks OR bus OR buses OR van OR vans OR tram OR trams OR train/exp OR trains OR railroad/
exp OR railroads/exp OR taxi OR taxis OR commercial* OR worker* OR working OR occupation*) AND (driver* OR driving)
OR ((pilot* AND (airline* OR aviation/exp OR airplane* OR aircraft* OR aeroplane* OR airship*))
OR captain* OR seafarer* OR sailor' OR seaman/exp OR pilots*
#4
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
nonmedical occupations/exp
#5
#1 AND #2 OR #3 OR #4
#6
#5 LIMIT humans AND LIMIT/embase
SCI & SSCI (Web of Science) (to 28.5.2007)
#1
random* OR "controlled clinical" OR "clinical trial*" OR "double blind*" OR "single blind*" OR ((singl* OR doubl* OR trebl* OR
tripl*) AND (mask* OR blind*)) OR placebo* OR "research design" OR comparativ* OR evaluation* OR "follow up" OR prospectiv*
OR effect* OR control* OR evaluation* OR program*
#2
drug OR drugs OR cannabi* OR opia* OR cocaine* OR amphetamine* OR phencyclidine* OR benzodiazepine* OR alcohol* OR
medication* OR prescription* OR medicament* OR pharmaceutical* OR sedative* OR intoxicat* OR drunk* OR drink* "substance
abuse" OR marijuana OR dui OR dwi)
#3
(lorry OR lorries OR truck OR trucks OR bus OR buses OR van OR vans OR tram OR trams OR train/exp OR trains OR railroad/
exp OR railroads/exp OR taxi OR taxis OR commercial* OR worker* OR working OR occupation*)) AND (driver OR drivers OR
driving) OR
captain* OR seafarer* OR sailor' OR seaman/exp OR pilots*
#5
#1 AND #2 AND #3
NIOSHTIC2, CISDOC and HSELINE (Silverplatter) (to 28.5.2007)
#1
random* or control* or allocation or double-blind or single-blind or clinical or "research design" or "follow up" or ((singl* or doubl*
or trebl* or tripl*) and (blind* or mask*)) or placebo* or comparativ* or evaluation or follow-up or prospectiv* or effect* or control*
or evaluation* or program*
#2
drug or drugs or cannabi* or opia* or cocaine* or amphetamine* or phencyclidine* or benzodiazepine* or alcohol* or medication* or
prescription* or pharmaceutical* or sedative* or intoxicat* or drunk* or drink* or marijuana or dui or dwi or "substance abuse"
#3
captain* or seafarer* or sailor* or seaman or pilots or ((drive* or driving) and (lorry or lorries or truck or trucks or bus or buses or van
or vans or tram or trams or train or trains or railroad* or taxi or taxis or commercial* or worker* or working or occupation*)) or ((pilot*
and (airline* or aviation or airplane* or aircraft* or aeroplane* or airship*))
#4
#1 AND #2 AND #3
PschINFO (Silverplatter) (to 29.5.2007)
#1
random* or control* or "clinical trial" or "clinical trials" or "double blind" or "single blind" or ((singl* or doubl* or trebl* or tripl*) and
(mask* or blind*)) or placebo* or "research design" or comparativ* or "follow up" or prospectiv* or effect* or control* or evaluation*
or program*
#2
drug or drugs or cannabi* or opia* or cocaine* or amphetamine* or phencyclidine* or benzodiazepine* or alcohol* or medication* or
prescription* or medicament* or pharmaceutical* or sedative* or intoxicat* or drunk* or drink* or "substance abuse" or marijuana or
dui or dwi
#3
captain* or seafarer* or sailor* or seaman or pilots or ((driver* or driving) and (lorry or lorries or truck or trucks or bus or buses or van
or vans or tram or trams or train or trains or railroad* or taxi or taxis or commercial* or worker* or working or occupation*))
#4
#1 AND #2 AND #3
Cochrane Library (Wiley InterScience) (to 29.5.2007)
#1
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
(drug or drugs or cannabi* or opia* or cocaine* or amphetamine* or phencyclidine* or benzodiazepine* or alcohol* or medication* or
prescription* or medicament* or pharmaceutical* or sedative* or intoxicat* or drunk* or drink* or "substance abuse" or marijuana or
dui or dwi ):tw,ab,kw.
#2
((driver* or driving) and (lorry or lorries or truck or trucks or bus or buses or van or vans or tram or trams or train or trains or railroad*
or taxi or taxis or commercial* or worker* or working or occupation*)) or captain* or seafarer* or sailor* or seaman or pilots or ((pilot*
and (airline* or aviation* or airplane* or aircraft* or aeroplane* or airship*))
#3
#1 AND #2
ERIC (ProQuest CSA) (to 29.5.2007)
#1
random* or clinical* or allocation or placebo* or ((singl* or doubl* or trebl* or tripl*) and (blind* or mask*)) or comparativ* or
evaluation or follow-up or prospectiv* or effect* or control* or evaluation* or program*
#2
drug* or cannabi* or opia* or cocaine* or amphetamine* or phencyclidine* or benzodiazepine* or alcohol* or medication* or prescrip-
tion* or medicament* or pharmaceutical* or sedative* or intoxicat* or drunk* or drink* or "substance abuse" or marijuana or dui or
dwi
#3
(driver* or driving) and (lorry or lorries or truck or trucks or bus or buses or van or vans or tram or trams or train or trains or railroad*
or taxi or taxis or commercial* or worker* or working or occupation* or commercial)) or captain* or seafarer* or sailor* or seaman or
pilots or ((pilot* or driver* or driving) and (airline* or aviation* or airplane* or aircraft* or aeroplane* or airship*))
#4
#1 and #2 and #3
ETOH (etoh.niaa.nih.gov) (to 31.5.2007)
Because of the limitations of the interface each term had to be searched separately from this database.
Protocol first published: Issue 2, 2007 Review first published: Issue 2, 2009 Clodagh Cashman conceptualised the review, took the lead in writing the protocol and wrote the sections collaborating with JosVerbeek, Jani Ruotsalainen, Birgit Greiner and Paul Beirne.
Jos Verbeek and Jani Ruotsalainen designed the systematic search strategies in collaboration with the Cochrane Occupational HealthField and Karen Blackhall of the Cochrane Injuries Group.
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
• University College Cork, Ireland.
• Health Research Board, Ireland.
• Finnish Institute of Occupational Health, Finland.
The inclusion criteria and the instrument for judging study quality were changed.
In the protocol we stated that we would include interrupted time-series (ITS) studies only when they used a control group. Whenconducting the review proper, we soon realised this was contradictory to our initial intention of including properly conducted ITSstudies. According to our definition, ITS studies have been conducted properly when they have conducted at least three outcomemeasurements before and after the intervention. The inclusion of a control group is therefore of less importance. The idea behindITS studies is to compare the situation before an intervention to the situation following its implementation (rather than interventionvs. control). We implemented this correction to the review inclusion criteria before we had an idea what this would do to the results.
Therefore ITS studies without a control group, but with three outcome measurements before and after the intervention, were included.
From other reviews using ITS studies ) we learned that there was a better instrument for judging quality () and that we should use that instrument instead of the one we had chosen (). The checklist was initiallychosen because in addition to randomised controlled trials it could also be applied to (non-randomised) controlled clinical trials. Sinceno randomised controlled trials or controlled clinical trials were included in the review we don't think this biased the results.
I N D E X T E R M S
Medical Subject Headings (MeSH)
∗Motor Vehicles [statistics & numerical data]; ∗ Substance Abuse Detection; Accidents, Occupational [∗ prevention & control; statistics &numerical data]; Alcoholism [diagnosis]; Substance-Related Disorders [∗diagnosis]; United States [epidemiology]; Workplace; Woundsand Injuries [epidemiology; ∗prevention & control] MeSH check words
Alcohol and drug screening of occupational drivers for preventing injury (Review)
Copyright 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

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