Sub-optimal adherence to combination anti-retroviral therapy and its associated factors according to self-report, clinician-recorded and pharmacy-refill assessment methods among HIV-infected adults in Addis Ababa

Adherence to combination antiretroviral therapy (cART) is generally high in most resource-limited settings. However, sub-optimal adherence occurs in a sizable proportion of patients, and is independently predictive of detectable viremia. We investigated sub-optimal adherence according to self-report, clinician-recorded, and pharmacy-refill assessment methods, and their associated factors among HIV-infected adults receiving cART in Addis Ababa, Ethiopia. Eight-hundred seventy patients who initiated cART between May 2009 and April 2012 were randomly selected, and 664 patients who were alive, had remained in clinical care and were receiving cART for at least six-months were included. Sub-optimal adherence was defined as patients' response of less than "all-of the time" to the self-report adherence question, or any clinician-recorded poor adherence during the six most recent clinic visits, or a pharmacy-refill of <95% medication possession ratio (MPR). Logistic regression models were fitted to identify factors associated with sub-optimal adherence. The average adherence level to cART, expressed as MPR, was nearly 97%. However, sub-optimal adherence occurred in 12%, 4%, and 27% of patients according to self-report, clinician-recorded, and pharmacy-refill measures, respectively. More satisfaction with social support was significantly associated with less sub-optimal adherence according to self-report and clinician-record. Younger age, lower educational level, and lower CD4 cell count at cART initiation were significantly associated with sub-optimal refill-based adherence. Findings from our large multi-center study suggest that sub-optimal adherence was present in up to a quarter of the patients, despite a high degree of average adherence to cART. Interventions aimed at preventing sub-optimal adherence should focus on improving social support, on younger patients, on patients with lower educational level, and on those who started cART at a lower CD4 cell count.