Schizophrenia (SZO) is a mental health condition that has important implications for morbidity and mortality outcomes, particularly for people living with HIV (PLHIV). As of yet, few studies have explored the impact of HIV and SZO on mortality.
Using the Comparative Outcomes and Service Utilization Trends cohort study, a population-based retrospective cohort study examining health outcomes and service use of PLHIV and a 10% random sample of individuals in British Columbia (BC), SZO prevalence and mortality outcomes were estimated from 1998-2013. Prevalence of SZO was assessed using physician and hospital-based administrative data and International Classification of Disease 9/10 codes. Survival time by HIV-status was accessed by a Kaplan-Meier (KM) plot, with log-rank test for comparison. Age and sex–adjusted mortality rates were calculated by using 2016 Canada population as reference. The association between HIV and all-cause mortality among SZO+ individuals were examined using logistic regression.
Of 515,913 BC residents accessing medical services from 1998-2013 in our study sample, 2.6% (n=13,412) were PLHIV and were significantly more likely to be SZO+ compared to HIV- individuals (6.3% vs. 1.1%, p<0.001). Compared to SZO+/HIV-, SZO+/PLHIV were significantly (all p<0.001) more likely to be male (75% vs. 56%), live in an urban setting (91% vs. 88%), have a history of injection drug use (IDU) (75% vs. 20%), and ever be on anti-psychotic medication (49% vs. 39%). Age and sex standardized all-cause mortality rates (ASMR) were highest among PLHIV/SZO+ (66.9/1,000 person years [PY], 95%CI=50.6-83.1), compared to PLHIV/SZO- (SMR=39.5/1,000PY, 95%CI=36.6-42.3) and SZO+/HIV- (ASMR=28.2/1,000PY, 95%CI=26.5-30.0). The KM plot (Figure 1) indicate that time from SZO diagnosis to death was significantly shorter among PLHIV compared to HIV- individuals (p<0.001). In a confounding logistic regression model of all SZO+ individuals, HIV-status remained significantly associated with mortality (aOR=2.31, 95%CI=1.84-2.89), controlling for sex, baseline age, and IDU.
PLHIV experience a six-times higher SZO prevalence compared to HIV- individuals, and among SZO+ individuals HIV is a risk factor for mortality. Moreover, PLHIV/SZO+ have higher mortality rates than PLHIV/SZO-. Physicians working with PLHIV/SZO+ that have high levels of IDU, should closely monitor treatment for SZO and HIV, so as to reduce mortality for this under-served, high-risk population.