LAUSR

The potency of modern antiretroviral therapy (ART) allows for greater forgiveness to missed doses while still achieving, and maintaining, viral suppression. However, imperfect ART adherence, even if sufficient to maintain viral suppression, has been associated with adverse clinical outcomes. ART adherence can be objectively quantified using tenofovir diphosphate (TFV-DP) in dried blood spots (DBS), a biomarker of cumulative adherence that is predictive of future viremia- even among persons with HIV (PWH) with an undetectable HIV viral load (HIV VL). Within a prospective cohort of PWH on tenofovir disoproxil fumarate (TDF)-including ART, mismatch between drug concentration and HIV VL (i.e., low concentrations of TFV-DP in DBS in the setting of viral suppression with subsequent viremia at the following visit) was observed more frequently in PWH who were Black (36% vs. 15%; p=0.04), had BMI >30 kg/m2 (40% vs. 13%; p=0.01), and reported <100% 3mo (68% vs. 50%; p=0.005) and 30d (56% vs. 31%; p=0.001) adherence, compared to PWH without mismatch. Identifying PWH at risk for future viremia could help clinicians implement targeted, timely interventions prior to episodes of breakthrough viremia.