HIV Infection Is Associated with a Higher Risk of Death from Drug Overdose

The aim of this prospective cohort study was to quantify the association of HIV infection with overdose mortality and explore the potential mechanisms.

A total of 1927 actively injecting drug users who were HIV seronegative at baseline, of whom 308 later HIV seroconverted, were followed semi-annually until death from 1988 to 2001. Survival analyses using marginal structural and standard Cox models were used to evaluate the effect of HIV infection on the risk of overdose mortality.

Results

·         Overdose death rates were higher in HIV-seropositive than HIV-seronegative drug users: 13.9 and 5.6 per 1000 person-years, respectively (P < 0.01).

·         The hazard ratio (HR) was 2.54 for the marginal structural model and 2.06 for the standard Cox model, both adjusted for demographics, drug injection characteristics, alcohol abuse, substance abuse treatment, and sexual orientation.

·         Adjusting for possible time-varying mediators (i.e. drug use, medical conditions and healthcare access) in extended marginal structural models reduced the effect of HIV on overdose mortality by 30%.

·         Abnormal liver function was associated with a higher risk of overdose mortality; adjustment for this further reduced the effect of HIV on overdose mortality.

The authors conclude, “HIV infection was associated with a higher risk of overdose mortality. Drug use behavior, systematic disease and liver damage associated with HIV infection appeared to account for a substantial portion of this association.”

Discussion

The major finding of this study was the observation of a higher rate of overdose mortality among those with HIV infection. Factors accounting for approximately 35% of the association between HIV infection and overdose death included a combination of drug use behavior, medical conditions, healthcare utilization and abnormal liver function.

These data are in contrast to a few previous studies that have failed to identify a significant association of HIV infection and overdose mortality.

The authors note that their findings suggest that special attention about overdose prevention should be directed to individuals with HIV infection who use illicit drugs. Potential interventions include counseling at post-HIV testing counseling, closer monitoring and easier access of drug abuse treatment to drug users with HIV infection, and in cities where naloxone is available, training those with authority to prescribe or administer naloxone to drug users, which has been shown substantially to reduce overdose morbidity and mortality.

06/03/05

Reference
C Wang and others. The effect of HIV infection on overdose mortality. AIDS 19(9): 935-942. June 10, 2005.