Modeling the HIV cascade of care using routinely collected clinical data to guide programmatic interventions and policy decisions

Abstract

Background: The HIV care cascade is a framework to examine effectiveness of HIV programs and progress toward global targets to end the epidemic but has been conceptualized as a unidirectional process that ignores cyclical care patterns. We present a dynamic cascade that accounts for patient “churn,” and apply novel analytic techniques to readily available clinical data to robustly estimate program outcomes and efficiently assess progress towards global targets. Methods: Data were assessed for 35,649 people living with HIV and receiving care at 78 clinics in East Africa between 2014-2020. Patients were aged >15 years and had >1 viral load measurements. We used multi-state models to estimate the probability of being in 1 of 5 states of a dynamic HIV cascade: (1) in HIV care but not on antiretroviral therapy (ART); (2) on ART; (3) virally suppressed; (4) in a gap-in-care; and (5) deceased; and compared these among subgroups. To assess progress towards global targets, we summed those probabilities across patients and generated population-level proportions of patients on ART and virally suppressed in mid-2020. Results: One year following enrollment, 2.8% of patients had not initiated ART, 86.7% were receiving ART, 57.4% were virally suppressed,10.2% were disengaged from care, and 0.3% had died. At 5 years, the proportion on ART remained steady but viral suppression increased to 77.2%. Of those aged 15-25, >20% had disengaged from care and <60% were virally suppressed. In mid-2020, 90.1% of the cohort was on ART, 90.7% of whom had suppressed virus. Conclusion: Novel analytic approaches can characterize patient movement through a dynamic HIV cascade and, importantly, by capitalizing on readily available data from clinical cohorts, offer an efficient approach to estimate population-level proportions of patients on ART and virally suppressed. Significant progress towards global targets was observed in our cohort but challenges remain among younger patients.