Assessment of TB treatment adherence using computer-assisted self-interviewing

OBJECTIVES: To evaluate the correlation and agreement between computer-assisted self-interviewing (CASI) and home-based unannounced pill counts (HUPC) for assessing anti-TB medication adherence (MA) and to examine the relationship between MA and treatment success.METHODS: Individual CASI-evaluated MA was compared three times with HUPC MA over the treatment course. The relationship between the two methodologies was determined using correlation coefficients (r) and intraclass correlation coefficients (ICC). The association between MA and efficacy was evaluated using odds ratios (ORs).RESULTS: According to CASI assessments, MA rates of 52 TB patients were 92.2%, 90.6%, and 87.5% at Week 4, 8 and 16–24, respectively, with a strong correlation (r > 0.76) and agreement (ICC > 0.88) with HUPC evaluations. CASI missed one-third of the non-adherent cases reported by HUPC based on patient adherence status. The treatment success rates of patients with >90% adherence, as measured by CASI and HUPC, did not differ significantly; however, >85% adherence was associated with higher treatment success (OR 45.1) than 90% adherence (OR 21.9).CONCLUSION: CASI results were comparable to those of HUPC. As it increased the likelihood of successful treatment, a threshold of >85% may be more appropriate than >90% for defining medication-adherent patients.