Pill counts and drug level determinations do not predict therapy failure due to drug resistance in a resource-limited setting

• Published in: Antiviral therapy Vol. 18; p. A76
• Main Authors: Aitken, S C, Slabbert, M, Kromdijk, W, Tempelman, H, Schrooders, P, Huitema, A DR, Schuurman, R, Wensing, A MJ
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• Subjects: Human immunodeficiency virus 1
• ISSN: 1359-6535

HIV-1 treatment management in resource-limited settings mostly involves clinical and, limited, immunological monitoring. Counselling and pillcounts are used to improve adherence, and are considered a predictor for selection of drug resistance (HIVDR), and hence a tool to guide therapy switching. We assessed the association of pill-counts and drug-levels with actual HIVDR in South African patients. HIVDR-genotyping and drug-level determination were performed on dried blood spots (DBS) collected from 66 patients experiencing virological failure. From DBS, calculated plasma levels [greaterthan]3.0 mg/l for nevirapine and [greaterthan]1.0 mg/l for efavirenz were considered adequate. Lopinavir levels were scored as detectable/not. Structured pill-counts over the year prior to DBS were reported as a percentage and averaged. We have shown that pill-counts and drug-level determination were not associated with predicting the presence of HIVDR. Albeit, pill-counts may be a good method for adherence counselling, they are not sufficient to base decisions on therapy switching.