Pharmacy Records: A Substitute for Viral-Load Monitoring in Resource-Poor Settings?

In resource-limited settings, the prohibitive cost of viral-load testing makes virologic success of antiretroviral treatment difficult to assess directly. The WHO recommends monitoring CD4-cell counts instead, but waiting for these counts to drop can result in suboptimal management. Investigators wondered whether estimating patients’ adherence levels using pharmacy records might provide an earlier clue to virologic failure.

Medical records and pharmacy claims were reviewed for almost 2000 HIV-infected adults in southern Africa who initiated NNRTI-based antiretroviral therapy. At both 6 months and 12 months, about 25% of patients experienced virologic failure (confirmed by viral-load testing). Estimated adherence ≤90% (defined as missing ≥1 monthly drug pick-up every 6 months) predicted virologic failure better than did change in CD4-cell count, both at 6 months and at 12 months; receiver operating curves supported the superiority of adherence as a measure of virologic success. In a variety of other statistical analyses, adherence levels were at least as accurate as CD4-cell levels in predicting virologic failure, whether defined as viral load >1000 copies/mL or >10,000 copies/mL.