Impact of Early versus Late Adherence to Highly Active Antiretroviral Therapy on Immuno-Virological Response: A 3-Year Follow-Up Study

Abstract

ObjectiveTo assess the impact of different patterns of adherence to highly active antiretroviral therapy (HAART), in particular, the relative impact of early and late adherence, on long-term immuno-virological response in HIV-infected individuals started on a protease inhibitor-containing regimen.DesignClinical, immuno-virological and self-reported adherence data were collected at 4 (M4), 12 (M12), 20 (M20), 28 (M28) and 36 (M36) months after HAART initiation in the French APROCO cohort.MethodsA standardized self-administered questionnaire classified patients as non-adherent, moderately or highly adherent at each visit. Stable viral suppression at both M28 to M36, and a CD4 cell increase >200 between M0 and M36 were used as outcome measures.ResultsOf the 582 patients followed regularly through M36, 360 patients had complete adherence data. Although 59.2% were highly adherent at M4, only 25.8% maintained consistent high adherence throughout the follow-up. High adherence at M4 was independently associated with both stable viral suppression at M28–M36 [OR (95% CI): 2.8 (1.4–5.5)] and a CD4 cell increase >200 during the same period [OR (95% CI): 3.9 (1.7–9.7)]. However, ‘moderately adherent’ patients between M12 and M36 had the same likelihood [OR (95% CI): 1.9 (1.1–3.2)] as patients who were always high adherent [OR (95% CI): 1.9 (1.1–3.2)] of achieving stable viral load suppression, relative to those who reported non-adherence episodes.ConclusionOptimizing adherence in the early months of treatment is crucial to ensure long-term immuno-virological success. Moderate deviations from high adherence during follow-up have a less negative impact. Priority should be given to interventions aimed to improve adherence in the early months of HAART.