<![CDATA[Tuberculosis remains a major public health problem in Indonesia, and medication nonadherence continues to reduce treatment success despite the availability of effective therapy. The Health Belief Model (HBM) provides a framework for understanding treatment adherence based on patients' health beliefs. This study aimed to analyze determinants of treatment adherence among pulmonary tuberculosis patients using the Health Belief Model approach in Pariaman City, Indonesia. A mixed-methods study with an explanatory sequential design was conducted from August 2023 to June 2024. The quantitative phase employed a cross-sectional design involving 107 pulmonary tuberculosis patients selected through proportional random sampling. The sample size was determined using the Lemeshow formula, yielding a minimum of 97 participants, with an additional 10% included to account for potential dropouts, resulting in a final sample of 107 patients. Independent variables included perceived susceptibility, perceived severity, perceived benefits, perceived barriers, and self-efficacy. The qualitative phase involved in-depth interviews with 12 purposively selected informants to explore program implementation related to treatment adherence. Poor perceptions were reported for susceptibility (43.9%), severity (41.1%), benefits (46.7%), barriers (44.9%), and self-efficacy (52.3%). Bivariate analysis showed that perceived severity (p=0.007) and perceived benefits (p<0.001) were significantly associated with treatment adherence. Multivariate analysis identified perceived benefits as the strongest determinant of treatment adherence (OR=5.103; 95% CI: 2.165-12.027; p<0.001). Qualitative findings revealed that limited human resources, funding constraints, and inconsistent patient education contributed to poor perceived benefits, supporting the quantitative finding that perceived benefits was the strongest determinant of adherence. Health authorities should strengthen patient education, ensure adequate human and financial resources, and implement standardized monitoring and counseling programs to improve treatment adherence and tuberculosis control outcomes.]]>
