Agreement Between Measures of Adherence to Isoniazid Preventive Therapy Among People With HIV in Uganda

Abstract

Background Isoniazid (INH) preventative therapy is recommended for people with HIV (PWH) in resource-constrained settings. Valid measures are needed to assess adherence. We aimed to examine agreement between measures overall and by level of social desirability. Methods PWH with latent TB were recruited in Mbarara, Uganda. Past 30-day adherence was measured by the number of days with pill bottle openings using a Medication Event Monitoring System (MEMS) and self-reported number of days pills taken. INH concentration (INH plus acetyl INH and their ratio) in hair samples was measured. We used Bland-Altman plots to examine agreement between adherence measures, and calculated the area under the receiver operator curve (ARUC) to determine if INH hair concentration predicted optimal MEMS-measured adherence (≥90%). Results 301 participants enrolled; 92% were virologically suppressed, and adherence was high. Median [IQR] number of pill bottle openings in 30 days were 28 [24, 30] compared to 30 [28, 30] via self-report. INH concentration was 36.2 [17.2, 62.4], and the INH:acetyl ratio was 2.43 [0.99, 3.92]. Agreement between self-reported and MEMS adherence was greater at more optimal adherence levels. INH:acetyl INH ratio was not predictive of optimal adherence according to MEMS (ARUC 0.62 (95% CI: 0.52, 0.72)) in a subset (n = 161). Conclusions Lower MEMS adherence levels compared to self-report suggest the need for objective adherence measures. Biologic measures have potential, although in this study INH concentration was not predictive of MEMS measured adherence. More data are needed to assess their accuracy.

Biomarker-confirmed suboptimal adherence to isoniazid preventive therapy among children with HIV in western Kenya

“…A high discrepancy between self or caregiverreported adherence and urine biomarker tests was also reported by a study that assessed adherence in HIVexposed infants enrolled in a TB prevention trial in western Kenya [31]. Several other studies have reported discrepancies between self-giver or caregiver reported versus biomarker-confirmed adherence [17,35]. The growing evidence that self-giver or caregiver reports overestimate adherence suggests the need for more objective measures of adherence to TB preventive therapy [17,35].…”

“…Several other studies have reported discrepancies between self-giver or caregiver reported versus biomarker-confirmed adherence [17,35]. The growing evidence that self-giver or caregiver reports overestimate adherence suggests the need for more objective measures of adherence to TB preventive therapy [17,35]. Biomarker confirmation of actual drug exposure provides a more accurate and objective measure of adherence [16,17,20] and could be useful in identifying nonadherent CLHIV in routine clinical practice.…”