Explaining adherence to tuberculosis treatment through the information-motivation-behavioral skills model: a PLS - SEM study in Indonesia

Abstract Background Tuberculosis is a serious public health issue because the success of treatment highly depends on adherence. In Serdang Bedagai, 48.87% of patients were reported to take their medication regularly for a period of less than six months. The purpose of this study was to explore the associations between Information, Motivation, and Behavioral Skills within an adapted IMB measurement model among tuberculosis patients in Serdang Bedagai Regency. Method The research uses an explanatory quantitative approach with a cross-sectional survey design. The sample consisted of 230 tuberculosis patients, category 1 as new patients who have never been treated or have taken Anti-Tuberculosis Drugs (OAT) for less than one month, probability sampling with cluster random sampling technique from six community health centers with high, medium, and low case categories. Data were collected using a Likert Scale questionnaire and analysed using Partial Least Squares Structural Equation Modelling (PLS-SEM 3). The measurement model consists of three indicators of Information, three indicators of Motivation, and four indicators of Behavioral Skills. All constructs meet the criteria for reliability and convergent validity, with composite reliability ranging from 0.811 to 0.826 and Average Variance Extracted from 0.523 to 0.614. Results The structural model shows no multicollinearity issues, with a VIF of 1.014. Information and Motivation together explain 8.2% of the variation in Behavioral Skills (R²=0.082), with low but positive predictive relevance (Q²=0.029). Information has a significant negative effect on Behavioral Skills (β=-0.226; t = 3.326; p = 0.001), while Motivation has a significant positive effect (β = 0.151; t = 2.049; p = 0.041). The coefficient of Information is greater than that of Motivation, but the direction of their influence is different, so it cannot be interpreted as a stronger positive influence. Conclusion The adapted IMB measurement model provided exploratory evidence regarding the associations between Information, Motivation, and adherence-related Behavioral Skills among tuberculosis patients. The findings should be interpreted as context-specific structural relationships rather than as evidence that the IMB model fully explains tuberculosis treatment adherence.