Driving under the influence (DUI) among patients in opioid maintenance treatment (OMT): a registry-based national cohort study.

AIMS: To investigate convictions for driving under the influence (DUI) before, during and after opioid maintenance treatment (OMT) and to examine factors associated with convictions for DUI during treatment.

DESIGN, SETTING AND PARTICIPANTS: Treatment data on all patients who started OMT in Norway between 1997 and 2003 (n = 3221) were cross-linked with national criminal records using unique person identifiers. Patients were followed over a 9-year period, before, during and in periods out of opioid maintenance treatment.

MEASUREMENTS: Data were formal charges leading to convictions recorded during four different time-periods: 3 years prior to application, waiting-list, in-treatment and in periods out of treatment.

FINDINGS: During OMT, convictions for DUI were reduced by almost 40% compared with pre-application levels. The conviction rate for DUI for males in the pre-application period was 9.59 per 100 person-years (PY) and for females, 3.44 per 100 PY. During OMT, rates of DUI convictions were reduced to 5.97 per 100 PY among men and to 1.09 per 100 PY among women. However, when estimating the effect of OMT on convictions for DUI, the interaction between gender and exposure to OMT was not statistically significant. Patients who remained in continuous treatment had fewer convictions for DUI during treatment compared with patients in discontinuous treatment. Compared with patients having no road traffic convictions during the pre-application period, patients with two or more pre-application convictions for DUI had higher odds [odds ratio (OR) = 3.69 (2.30-5.93)] for further convictions for DUI during OMT.

CONCLUSION: In Norway, patients receiving opioid maintenance treatment (OMT) have reduced convictions for driving under the influence (DUI) compared with their pre-treatment levels. Being male and having a previous history of several convictions for DUI were found to be important risk factors for convictions for DUI during OMT.