Results from multivariate Cox PH models indicating factors associated with mortality over the six-year follow-up period.

*Observed time in the study was calculated as the time from the start of methadone treatment to either death or study completion (30 June 2010), whichever occurred first.§PY: person-years, HR: hazard ratio, CI: 95% confidence interval.†Average methadone dose is calculated as the sum of all methadone doses divided by the number of days methadone was received.#Length of treatment is calculated as the total number of days that clients took methadone in the MMT clinics, than transfer to the number of years by dividing 365.‡Urine tests positive for opiates during treatment is calculated by the total number of routine urine drug tests that yielded positive results as a percentage of the total number of tests taken during the six years of follow-up.#Adjusting for confounding variables including living situation, injection in the past month, having relatives who were MMT patients.&Results of univariate Cox regression.