| Abstract | Aim
To assess whether risk of death increases during periods of treatment transition, and investigate the impact of supervised methadone consumption on drug-related and all-cause mortality.
Design
National Irish cohort study.
Setting
Primary care.
Participants
A total of 6983 patients on a national methadone treatment register aged 16–65 years between 2004 and 2010.
Measurement
Drug-related (primary outcome) and all-cause (secondary outcome) mortality rates and rate ratios for periods on and off treatment; and the impact of regular supervised methadone consumption.
Results
Crude drug-related mortality rates were 0.24 per 100 person-years on treatment and 0.39 off treatment, adjusted mortality rate ratio 1.63 [95% confidence interval (CI) = 0.66–4.00]. Crude all-cause mortality rate per 100 person-years was 0.51 on treatment versus 1.57 off treatment, adjusted mortality rate ratio 3.64 (95% CI = 2.11–6.30). All-cause mortality off treatment was 6.36 (95% CI = 2.84–14.22) times higher in the first 2 weeks, 9.12 (95% CI = 3.17–26.28) times higher in weeks 3–4, compared with being 5 weeks or more in treatment. All-cause mortality was lower in those with regular supervision (crude mortality rate 0.60 versus 0.81 per 100 person-years) although, after adjustment, insufficient evidence exists to suggest that regular supervision is protective (mortality rate ratio = 1.23, 95% CI = 0.67–2.27).
Conclusions
Among primary care patients undergoing methadone treatment, continuing in methadone treatment is associated with a reduced risk of death. Patients' risk of all-cause mortality increases following treatment cessation, and is highest in the initial 4-week period.
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