Objectives:
To assess the level and correlates of biomarker-confirmed adherence to isoniazid (INH) preventive therapy (IPT) among children living with HIV (CLHIV).
Design:
This prospective cohort study assessed adherence among CLHIV on IPT in public sector HIV clinics from 2019 through 2020.
Methods:
Adherence was assessed by pill counts or caregiver- or self-reports, and urine biomarkers (in-house dipstick and IsoscreenTM©). Both urine biomarker tests detect INH metabolites within 48 hours of ingestion. Consistent adherence was defined as having positive results on either biomarker at all visits. Correlates of biomarker-confirmed nonadherence at each visit were evaluated using generalized estimating equations. The in-house dipstick was validated using IsoscreenTM© as the reference.
Results:
Among 97 CLHIV on IPT with adherence assessments, median age was 10 years (IQR 7–13). All were on ART at IPT initiation (median duration 46 months [IQR 4–89]); 81% were virally suppressed (<1000 copies/ml). At all visits, 59% (n = 57) of CLHIV reported taking ≥80% of their doses, while 39% (n = 38) had biomarker-confirmed adherence. Viral non-suppression (adjusted risk ratio [aRR] = 1.65; 95% CI 1.09 – 2.49) and the sixth month of IPT use (aRR = 2.49; 95% CI 1.34 – 4.65) were independent correlates of biomarker-confirmed nonadherence at each visit. Sensitivity and specificity of the in-house dipstick were 98.1% (94.7% - 99.6%) and 94.7% (88.1% - 98.3%), respectively, versus IsoscreenTM©.
Conclusions:
Biomarker-confirmed adherence to IPT was sub-optimal and was associated with viral non-suppression and duration of IPT. Urine dipstick testing may be useful in assessing adherence to IPT in clinical care.