Forecasting multimorbidity in aging people with HIV using a microsimulation model

While life expectancy has significantly increased among people living with HIV (PLWH) due to effective antiretroviral therapy, aging-related non-communicable diseases and multimorbidity have emerged as critical challenges. Understanding the evolving health needs of PLWH is essential to guiding healthcare planning and interventions. We developed a new microsimulation model that integrates longitudinal clinical and administrative data to project the health trajectories of PLWH in British Columbia from 2019 to 2034. High prevalence conditions, such as cardiovascular disease (CVD), non-AIDS-related cancers, chronic liver disease (CLD), hypertension, chronic obstructive pulmonary disease (COPD), and mood and anxiety disorders (MANX), were included in the model. Results were stratified by age and sex. Here we show that by 2034, nearly half of PLWH will be aged 60 years or older, and more than one-quarter will live with at least three additional chronic conditions. CVD is projected to nearly double (8.4–14.8%), cancers to rise from 8.9 to 17.2%, while MANX will remain the most common comorbidity, affecting about half of PLWH. Sex differences are pronounced; females show higher rates of multimorbidity involving MANX, CLD, and COPD, whereas males show higher prevalence of non-AIDS-related cancers and CVD. These findings highlight the urgency of preparing for a sharp increase in multimorbidity and demonstrate the value of forecasting tools to guide integrated models of care for aging PLWH.