Risk of motor vehicle collisions after methadone use: A systematic review and meta-analysis

Methadone maintenance therapy is a leading treatment strategy for stabilizing and rehabilitating patients with opioid dependence; however, findings related to the risk of motor vehicle collisions after methadone use have been conflicting. In the present study, we compiled the available evidence on the risk of motor vehicle collisions after methadone use.

We completed a systematic review and meta-analysis of studies identified on six databases. Two reviewers independently screened the identified epidemiological studies, extracted data, and used the Newcastle-Ottawa Scale to assess the quality of the studies. Risk ratios were retrieved for analysis, conducted using random-effects model. Sensitivity analyses, subgroup analyses, and tests for publication bias were conducted.

Among 1446 identified relevant studies, a total of 7 epidemiological studies enrolling 33226142 participants met the inclusion criteria. Overall, study participants with methadone use had a higher risk of motor vehicle collisions than did those without methadone use (pooled relative risk 1.92, 95% CI 1.25-2.95; number needed to harm 11.3, 95% CI 5.3-41.6); the I² statistic was 95.1%, indicating substantial heterogeneity. Subgroup analyses revealed that database type explained 95.36% of the between-study variance (p = 0.008). Egger's (p = 0.376) and Begg's (p = 0.293) tests revealed no evidence of publication bias. Sensitivity analyses indicated that the pooled results were robust.

The present review revealed that methadone use is significantly associated with a nearly doubled risk of motor vehicle collisions. Therefore, clinicians should exercise caution in implementing methadone maintenance therapy for drivers.