Mortality risk factors and excess mortality in a cohort of cocaine users admitted to drug treatment in Spain ★

We assessed mortality risk factors and excess mortality compared to the general population in two Spanish sub-cohorts of 8,825 cocaine and heroin users (CHUs) and 11,905 only cocaine users (OCUs) aged 15–49 admitted to drug treatment. Heroin use (among all cocaine users), no-regular employment and drug injection (among CHUs and OCUs), daily cocaine use and previous drug treatment (among CUs), and death before 2005 and > 10 years of heroin use (among CHUs) were clearly associated with higher mortality in Cox regression. Excess mortality was assessed by the directly standardized mortality rate ratio, which was higher in CHUs (14.3; 95% CI: 12.6–16.2) than CUs (5.1; 95% CI: 4.3–6.0) and in women than men, especially among OCUs (8.6; 95% CI: 7.5–10.0 vs. 3.5; 95% CI: 3.3–3.8); it decreased with age among CHUs, but did not decrease overall during 1997–2008. OCUs excess mortality was considerable and showed no signs of decline, suggesting the need for improved treatment and prevention interventions.