Patient Determinants and Effects on Adherence of Adverse Drug Reactions to Tuberculosis Treatment: A Prospective Cohort Analysis.

Abstract

Background: Adverse drug reactions (ADRs) to tuberculosis (TB) medications make treatment completion challenging. We investigated the impact of alcohol, human immunodeficiency virus (HIV), and other patient determinants on ADRs and treatment adherence.

Methods: We administered monthly ADR questionnaires to participants with TB in Worcester, South Africa. Adherence was defined as the proportion of observed doses on days when directly observed therapy was attempted. We used regression modeling to identify associations between age, sex, HIV status, alcohol, and smoked substance use with ADRs and adherence.

Results: Of 286 participants, 70 (24.5%) had moderate alcohol use (phosphatidylethanol [PEth], 20-200 ng/mL), 81 (28.3%) had heavy alcohol use (PEth, >200 ng/mL), and 81 (28.3%) had HIV. A total of 156 (54.5%) reported ≥1 ADR, with maximum severity of moderate (75.6%) or mild (22.4%). Alcohol use and HIV were not associated with ADRs. The presence of ≥1 comorbidity compared with none was associated with a 46% increase in the risk of ADRs (P = .01). Nearly 70% of participants had ≥80% adherence. Among participants with moderate or severe ADRs, HIV with CD4 count <200 cells/µL compared with no HIV (rate ratio = 1.71, P = .01), moderate or severe alcohol use compared with low (rate ratio = 1.55, P = .01 and rate ratio = 1.69, P = .01), and smoked substance use compared with none (rate ratio = 1.37, P = .04) were associated with increased missed doses.

Conclusions: Half of participants on TB treatment experienced ADRs, but most remained adherent to treatment. Among participants with moderate or severe ADRs, those with poorly controlled HIV, alcohol use, or smoked substance use had lower adherence.