Markers of poor adherence among adults with HIV attending Themba Lethu HIV Clinic, Helen Joseph Hospital, Johannesburg, South Africa

BACKGROUND: To date, there is no consensus on ideal ways to measure antiretroviral treatment (ART) adherence in resource limited settings. This study aimed to identify markers of poor adherence to ART. METHODS: Retrospective data of HIV-positive ART-naïve adults initiating standard first-line ART at Themba Lethu Clinic, Helen Joseph Hospital, Johannesburg, South Africa from April 2004 to December 2011 were analysed. Poisson regression models with robust error variance were used to assessed the following potential markers of poor adherence ‘last self-reported adherence, missed clinic visits, mean corpuscular volume (MCV), CD4 count against definition of adherence, suppressed HIV viral load using traditional test metrics’. RESULTS: A total of 11 724 patients were eligible; 1712 (14.6%) had unsuppressed viral load within 6 months after initiating ART. The main marker of poor adherence was a combination of change in CD4 count and MCV; change in CD4 ≥expected and change in MCV <14.5 fL (RR 2.82, 95% CI 2.16–3.67), change in CD4 <expected and change in MCV <14.5 fL (RR 5.49, 95% CI 4.13–7.30) compared to change in CD4 ≥expected and change in MCV ≥14.5 fL. CONCLUSIONS: A combination of less than expected increase in CD4 and MCV at 6 months after treatment initation was found to be a marker of poor adherence. This could help identify and monitor poor treatment adherence in the absence of viral load testing.