HIV, schizophrenia, and all-cause mortality: A population-based cohort study of individuals accessing universal medical care from 1998 to 2012 in British Columbia, Canada

Abstract Schizophrenia is a severe mental illness with important implications for morbidity and mortality. This population-based cohort study examined the impact of schizophrenia diagnoses on all-cause mortality among a sample of people living with HIV (PLHIV) and a 10% random sample of individuals living without HIV (HIV-) in British Columbia (BC), through a data linkage between the BC Centre for Excellence in HIV/AIDS and Population Data BC's data holdings. Schizophrenia diagnoses were identified via International Classification of Diseases version 9 and version 10 codes. Age- and sex-adjusted all-cause mortality rates from January 1st, 1998 to December 31st, 2012 were calculated. Multivariable logistic models assessed (1) HIV status and mortality among individuals diagnosed with schizophrenia, (2) schizophrenia diagnosis and mortality among PLHIV, and (3) correlates of mortality among PLHIV concurrently diagnosed with schizophrenia (HIV+/SZO+). From 1998 to 2012, 6.3% of those with HIV had a schizophrenia diagnosis, compared to 1.1% of those without HIV. While significant declines in mortality rates were observed throughout the study period, mortality rates were highest among HIV+/SZO+. After adjustment for substance use disorder and age at baseline, HIV+/SZO+ had a 2.64 times greater odds of mortality (95% confidence interval [CI] = 2.14–3.25) compared to HIV-/SZO+. For PLHIV, a schizophrenia diagnosis was not associated with mortality after controlling for potential confounders (adjusted odds ratio [aOR] = 0.90, 95%CI = 0.74–1.09). Among HIV+/SZO+, age, history of injection drug use, ever having an AIDS-defining illness, and never being on anti-psychotic medication or accessing psychiatric services were associated with mortality. Efforts should be made to identify and link to care individuals disproportionately affected by schizophrenia and excess mortality, including those living with HIV.