Antiretroviral drug concentrations in hair are associated with virologic outcomes among young people living with HIV in Tanzania

Tabb ZJ, Mmbaga BT, Gandhi M, Louie A, Kuncze K, Okochi H, Shayo AM, Turner EL, Cunningham CK, Dow DE
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We assessed the relationship of self-reported adherence versus antiretroviral therapy (ART) concentrations in hair with virologic outcomes among young people living with HIV.


This was a cross-sectional study that enrolled young people living with HIV age 11-24 years, who attended a youth HIV clinic in Moshi, Tanzania.


ART adherence was assessed by self-report, drug concentration in hair samples, and plasma HIV-1 RNA measurements. Those with virologic failure, defined as plasma HIV-1 RNA more than 400 copies/ml, had genotypic resistance assessed. Receiver operating characteristic curves were used to evaluate ART-concentration threshold cutoffs for virologic suppression, after excluding those with known high-level resistance mutations.


Among 280 young people enrolled, 227 were included in the final analysis. Seventy-two (32%) self-reported inadequate adherence and 91 (40%) had virologic failure. Hair ART-concentration (P < 0.001), but not self-reported adherence (P = 0.53), was associated with virologic outcome. Sixty-seven (74%) of those with virologic failure had resistance testing performed, of whom 60% had high-level resistance. Receiver operating characteristic curves demonstrated moderate or high classification performance for association with virologic suppression with specific hair ART-concentration cutoffs for lopinavir (1.8 ng/mg), efavirenz (1.04 ng/mg), and nevirapine (33.2 ng/mg).


Hair ART-concentrations were significantly associated with virologic outcomes among young people living with HIV. ART-concentration thresholds associated with virologic suppression are proposed. Hair analysis may provide a noninvasive, cost-effective adherence assessment tool in settings with limited second and third-line treatment options.