Sex-Based Differences in Rates, Causes, and Predictors of Death Among Injection Drug Users in Vancouver, Canada

Abstract

In the present study, we sought to identify rates, causes, and predictors of death among male and female injection drug users (IDUs) in Vancouver, British Columbia, Canada, during a period of expanded public health interventions. Data from prospective cohorts of IDUs in Vancouver were linked to the provincial database of vital statistics to ascertain rates and causes of death between 1996 and 2011. Mortality rates were analyzed using Poisson regression and indirect standardization. Predictors of mortality were identified using multivariable Cox regression models stratified by sex. Among the 2,317 participants, 794 (34.3%) of whom were women, there were 483 deaths during follow-up, with a rate of 32.1 (95% confidence interval (CI): 29.3, 35.0) deaths per 1,000 person-years. Standardized mortality ratios were 7.28 (95% CI: 6.50, 8.14) for men and 15.56 (95% CI: 13.31, 18.07) for women. During the study period, mortality rates related to infection with human immunodeficiency virus (HIV) declined among men but remained stable among women. In multivariable analyses, HIV seropositivity was independently associated with mortality in both sexes (all P < 0.05). The excess mortality burden among IDUs in our cohorts was primarily attributable to HIV infection; compared with men, women remained at higher risk of HIV-related mortality, indicating a need for sex-specific interventions to reduce mortality among female IDUs in this setting.

Reducing rates of preventable HIV/AIDS-associated mortality among people living with HIV who inject drugs

“…Recent data from The Joint United Nations Programme on HIV/AIDS described a 19% decline in AIDS-related deaths from 2011 to 2014, and a 35% decline from 2005 to 2014 [1**]. Among HIV-positive PWID however, the leading cause of death remains HIV/AIDS-related causes [2,3**,7,29,30,31*,32–34,35*,36**,37], reflecting suboptimal levels of ART access, and adherence in this population.…”

“…Additionally, incarceration [1**,43] and personal violence [3**,7,10*] remain persistent issues among HIV-positive PWID, with research demonstrating increased rates of suicides [7,44] being independently associated with a history of IDU (adjusted hazard ratio: 3.95; confidence interval: 1.99 – 7.86) [44]. Studies conducted in settings without universal healthcare may not be able to distinguish the effect of the aforementioned factors independent of the influence of financial need.…”

“…These results were echoed in a study from Melbourne, Australia, where PWID on HIV treatment were no more likely to experience AIDS or death than non-injectors [47]. More recently, Hayashi and colleagues [3**] reported rates and predictors of death among HIVpositive PWID in the context of a province-wide treatment as prevention (TasP) initiative aimed at improving access and adherence to ART in British Columbia. The 18-year cohort study of com- munity recruited HIV-positive PWID showed slow declines in HIV-related death in the late 1990s to early 2000s with high overall levels of mortality among PWID.…”

“…The 18-year cohort study of com- munity recruited HIV-positive PWID showed slow declines in HIV-related death in the late 1990s to early 2000s with high overall levels of mortality among PWID. Significant reductions in HIV-related mortality rates were observed among PWID from 2010 onward, coinciding with TasP-based efforts to scale-up treatment in this population [3**]. Such studies add to the growing consensus that where care is taken to address ART access and adherence barriers faced by HIV-positive PWID, this population can experience the same outcomes as non-injecting PLHIV, including improved life expectancy.…”

“…Improved tolerability, safety, and efficacy of therapies, in addition to scale-up of strategies to promote access and adherence to ART, have led to dramatic declines in all-cause mortality of people living with HIV (PLHIV) across a variety of settings and among diverse populations [1**,2,3**,4]. …”