53: An Emulated Trial Approach to Assess the Impact of Time-Updated Retention on Virological Failure

Thomas M. Menino Convention & Exhibition Center 

We assessed the impact of retention in care on virological failure in people with HIV (PWH), ≥18 years old, and enrolled in North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD). Previous work looked at time-fixed retention definitions (retained in both of the first 2 years). We enhanced this by implementing a nested trial approach with time-updated and lagged retention (attending ≥2 visits >90 days apart in the prior year) and multiple baselines per person. Additional time-updated and lagged covariates (diabetes diagnosis, hypertension diagnosis, AIDS diagnosis, age, ART medication receipt, and year in study) and time-fixed variables (HIV acquisition risk, NA-ACCORD location, sex, and race/ethnicity) were included. Using a Cox model with treatment and censoring weights, time-updated retention had a 25% decrease in hazards of virological failure (HR: 0.70-0.79) compared to the time-fixed result of a 35% decrease (HR: 0.62-0.68). The emulated trial method allows us to include time-updated data, leading to a more accurate depiction of the covariates' associations with the time-dependent outcome. This method enhanced our understanding of the HIV care continuum.

emulated trial

nested trial

HIV

time-to-event

time varying covariates

weighted Cox regression 

Section on Statistics in Epidemiology