In a retrospective cohort study of methadone users performed through data obtained from a primary care prescription registry in Tayside, Scotland, McCowan et al examined the interaction of patient related factors and prescribing factors at the individual level and assess their independent impact on the risk of both all-cause mortality and drug dependent cause specific mortality (McCowan, Kidd et al. 2009). Overall, 181 (8%) people died among 2378 subjects with a median follow-up of 4.38 years. Overuse of methadone, history of psychiatric admission, and increasing comorbidity were all associated with an increase in all-cause mortality. Longer duration of use (adjusted hazard ratio 0.95, 0.94 to 0.96), history of having urine tested (0.33, 0.22 to 0.49), and increasing time since last filled prescription were protective in relation to all-cause mortality. These factors are likely to be markers of people who are stabilised on maintenance treatment and engaged in monitoring procedures or who have successfully completed a methadone treatment reduction programme. This community based study gives a clear indication of the prescribing, monitoring, and management of patients in OMT and the subsequent impact on all cause and drug dependent mortality. This study provides evidence that recommendations on best practice (including specifically performing UDS) improve patients' outcomes.