Heroin was the primary drug used by 77% of the sample, with a median of 9.5 (range <1, 39) years of use and injecting. The majority (98%) of the sample injected heroin; 14% of the sample had been injecting heroin for three years or less and 80% for more than three years (18 cases had missing data for this variable). Those who did not inject heroin were excluded from analysis pertaining to injecting.
