Antiretroviral Refill Adherence Correlates with, But Poorly Predicts Retention in HIV Care.

If antiretroviral refill adherence could predict non-retention in care, it could be clinically useful. In a retrospective cohort study of HIV-infected adults in Philadelphia between October 2012 and April 2013, retention in care was measured by show versus no-show at an index visit. Three measures of adherence were defined per person: (1) percent of doses taken for two refills nearest index visit, (2) days late for last refill before index visit, and (3) longest gap between any two refills. Of 393 patients, 108 (27.4 %) no-showed. Adherence was higher in the show group on all measures with longest gap having the greatest difference: 40 days (IQR 33-56) in the show versus 47 days (IQR 38-69) in the no-show group, p < 0.001. Yet, no cut-points of adherence adequately predicted show versus no-show. Antiretroviral adherence being associated, but a poor predictor of retention suggests that these two behaviors are related but distinct phenomena.