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.