Predictors of accidental fatal drug overdose among a cohort of injection drug users

Objectives. This study evaluated factors associated with accidental fatal d rug overdose among a cohort of injection drug users (IDUs). Methods. In a prospective cohort study of 2849 IDUs in King County, Washing ton, deaths were identified by electronically merging subject identifiers w ith death certificate records. Univariate and multivariate Cox regression a nalyses were performed to identify predictors of overdose mortality. Results. Thirty-two overdoses were observed. Independent predictors of over dose mortality were bisexual sexual orientation (relative risk [RR] = 4.86; 95% confidence interval [Cl] = 2.30, 13.2), homelessness (RR = 2.30; 95% C I = 1.06, 5.01), infrequent injection of speedballs (RR = 5.36; 95% CI = 1. 58, 18.1), daily use of powdered cocaine (RR = 4.84; 95% CI = 1.13, 20.8), and daily use of poppers (RR = 22.0; 95% CI = 1.74, 278). Conclusions. Sexual orientation, homelessness, and drug use identify IDUs w ho may benefit from targeted interventions.