Validating Five Questions of Antiretroviral Nonadherence in a Public-Sector Treatment Program in Rural South Africa

Abstract

Simple questions are the most commonly used measures of antiretroviral treatment (ART) adherence in subSaharan Africa (SSA), but rarely validated. We administered five adherence questions in a public-sector primary care clinic in rural South Africa: 7-day recall of missed doses, 7-day recall of late doses, a six-level Likert item, a 30-day visual analogue scale of the proportion of doses missed, and recall of the time when an ART dose was last missed. We estimated question sensitivity and specificity in detecting immunologic (or virologic) failure assessed within 45 days of the adherence question date. Of 165 individuals, 7% had immunologic failure; 137 individuals had viral loads with 9% failure detected. The Likert item performed best for immunologic failure with sensitivity/specificity of 100%/5% (when defining nonadherence as self-reported adherence less than ''excellent''), 42%/55% (less than ''very good''), and 25%/95% (less than ''good''). The remaining questions had sensitivities 17%, even when the least strict cutoffs defined nonadherence. When we stratified the analysis by gender, age, or education, question performance was not substantially better in any of the subsamples in comparison to the total sample. Five commonly used adherence questions performed poorly in identifying patients with treatment failure in a public-sector ART program in SSA. Valid adherence measurement instruments are urgently required to identify patients needing treatment support and those most at risk of treatment failure. Available estimates of ART adherence in SSA are mostly based on studies using adherence questions. It is thus unlikely that our understanding of ART adherence in the region is correct.

A Self-Reported Adherence Measure to Screen for Elevated HIV Viral Load in Pregnant and Postpartum Women on Antiretroviral Therapy

“…Reviews have shown that self-reported measures range from single items asking for the number of prescribed doses missed in a specified time period to numerous complex items requiring detailed recall; very few studies report using the same self-reported adherence measure, making it difficult to compare results across studies [9, 21, 23]. An analysis in South Africa evaluating the performance of five commonly used self-reported adherence questions found that all questions were poor predictors of virologic and/or immunologic failure [36]. Similarly, another study in Cape Town using a short adherence scale in HIV-infected adults found no correlation between the scale score and having a detectable VL [37].…”

Interventions to increase antiretroviral adherence in sub-Saharan Africa: a systematic review of evaluation studies

“…101-103 Health workers (including those involved in the care of the control group in a DOT intervention) usually lack direct knowledge of patients’ pill taking behaviour and may thus misestimate true adherence. Objective measurement instruments, such as pharmacy refill data, pill count or medication events monitoring system (MEMS), may not necessarily reflect true pill-taking if patients discard pills or obtain ART from friends, family members, or from pharmacies that are not captured in the refill data.…”

Predictors of Nonadherence to Antiretroviral Therapy among HIV-Infected Adults in Dar es Salaam, Tanzania

“…[4][5][6][7] The methods of assessing nonadherence are diverse, 8,9 sometimes cumbersome to implement and may not actually correlate with immunologic or virologic failure. 10 In addition, factors associated with nonadherence to ART vary by social, cultural, and local contexts. 11 Studies of the predictors of nonadherence to ART among HIV-positive patients in areas of high HIV/AIDS burden are crucial to determine local factors associated with adherence to ART and to assist with the development and implementation of programs that maximize adherence.…”