Perceptions, Predictors, and Pathways: A Mixed Methods Study on TPT Adherence among Household Contacts of TB Cases

Tuberculosis (TB) remains a persistent global health threat, with the Philippines identified as one of the high-burden countries. Preventive measures such as Tuberculosis Preventive Treatment (TPT) are crucial for reducing the risk of active TB among household contacts of index cases. However, non-adherence continues to undermine program effectiveness. This study investigated the perceptions, predictors, and pathways of TPT adherence among household contacts using a sequential explanatory mixed methods design. The quantitative phase involved a cross-sectional survey of 112 household contacts of bacteriologically confirmed TB cases residing in Southville 3, Barangay Poblacion, Muntinlupa City. Data were collected using a structured questionnaire measuring socio-demographic characteristics, Health Belief Model (HBM) constructs (perceived susceptibility, severity, benefits, and barriers), self-efficacy, and perceived health system support. Statistical analysis, including descriptive statistics, chi-square tests, correlations, regression, and Partial Least Squares Structural Equation Modeling (PLS-SEM), was conducted to examine predictors of adherence and test mediation and moderation hypotheses. The qualitative phase employed in-depth interviews with 15 purposively selected participants representing diverse adherence behaviors. Thematic analysis was used to explore experiences, perceptions, and barriers to TPT completion. Findings revealed an alarmingly high non-adherence rate of 85.6%, with only 14.4% of participants completing the TPT regimen. Quantitative results showed that self-efficacy significantly mediated the relationship between HBM constructs and adherence, while health system support moderated the influence of self-efficacy on treatment outcomes. Qualitative insights highlighted side effects, stigma, economic difficulties, and inconsistent health system follow-up as critical barriers, while supportive provider interactions and family encouragement emerged as facilitators. The integration of findings demonstrated that while household contacts were aware of their susceptibility and recognized the benefits of TPT, perceived barriers often outweighed motivation, leading to treatment discontinuation. This study concludes that improving adherence requires not only strengthening education and risk communication but also addressing systemic and behavioral barriers. Recommendations include enhancing patient-centered counseling, managing side effects proactively, expanding reminder and follow-up systems, and tailoring interventions to household contexts. The results provide evidence-based guidance for health policymakers, practitioners, and TB program managers to reinforce TPT adherence and contribute toward the national and global goal of TB elimination.