Background. Adherence to first-line antiretroviral therapy (ART) may be an important indicator of adherence to second-line ART. Evaluating this relationship may be critical to identify patients at high risk for second-line failure, thereby exhausting their treatment options, and to intervene and improve patient outcomes. 

Methods. Adolescents and adults (n=436) receiving second-line ART were administered standardized questionnaires that captured demographic characteristics and assessed adherence. Optimal and suboptimal cumulative adherence were defined as percentage adherence of≥90% and<90% respectively. Bivariable and multivariable binomial regression models were used to assess the prevalence of suboptimal adherence percentage by pre-switch adherence status.

Results. 134/436 (30.7%) participants reported suboptimal adherence to second-line ART. Among 322 participants who had suboptimal adherence to first-line ART, 117 (36.3%) had suboptimal adherence to second-line ART compared to 17/114 (14.9%) who had optimal adherence to first-line. Participants who had suboptimal adherence to first-line ART were more likely to have suboptimal adherence to second-line ART (APR 2.4, 95% CI 1.5 – 3.9).

Conclusion. Adherence to first-line ART is an important predictor of adherence to second-line ART. Targeted interventions should be evaluated in patients with suboptimal adherence prior to switching into second-line therapy to improve their outcomes.