Background
People living with HIV (PLWH) and health systems caring for them were hit hard by the COVID-19 epidemic and illicit drug toxicity crisis. These challenges have been further compounded by voluntary and involuntary migration and displacement due to war, political violence, and, for PLWH, stigma and discrimination. These crises have tested the resilience of healthcare systems (i.e., the capacity to predict, absorb, recover from, and adapt to shocks). We developed a micro-simulation model to assess the resilience of a healthcare system under different shocking scenarios.
Methods
We used individual-based longitudinal data (2014-2023) from the HIV Drug Treatment Program (DTP) in British Columbia (BC), which provides free ART and care to all PLWH. Three scenarios were modeled: the COVID-19 pandemic, the illicit drug toxicity crisis, and migration into BC. The microsimulation included 8583 PLWH, representing DTP participants alive by December 2014, with age and sex randomly sampled from the DTP. The model simulated monthly status transitions from 2015 to 2033, classifying each individual as actively on ART, experiencing short- or long-term (i.e., >18 months) ART discontinuation, migrating to BC, or deceased (from overdose or other causes). New DTP participants were dynamically added over time. Transition probabilities were based on age, sex, and current state. Population projections were made for 2024-2033.
Results
Among the modeled scenarios, the COVID-19 pandemic had the least impact on the size and composition of the DTP population. In contrast, overdose mortality disproportionately affected females and individuals aged 50+. The DTP population is aging rapidly, with the proportion of those aged 70+ increasing eightfold between 2014 and 2033. This demographic shift is contributing to a rise in non-AIDS-related mortality, reshaping the DTP population. Migration (>100 PLWH per quarter) had the largest and most uncertain impact on population projections. Sustained migration for >2 years is projected to increase the DTP population by 10-22% over the next decade, especially among PLWH aged 30-50, a group prone to treatment churn (on-off ART).
Conclusions
While HIV services remain resilient in supporting the aging DTP population, there is a significant disconnect between HIV care and other critical services, particularly for aging and migrant populations. These service gaps may pose long-term challenges to the sustainability of the broader healthcare system and require urgent attention.