The development of an adherence to treatment scale for pulmonary TB

BACKGROUND Effective TB treatment requires consistent adherence, yet traditional assessments focus solely on medication intake and may miss important lifestyle factors. This study aimed to develop and evaluate the psychometric properties of the Adherence to TB Treatment Scale (ATTS), a new instrument covering both medication intake and lifestyle behaviours. METHOD The development followed seven steps: 1) defining TB treatment adherence through literature synthesis and a Delphi study, 2) generating an item pool from an extensive literature review, 3) using a four-point Likert scale for measurement, 4) assessing item validity, 5) conducting preliminary studies, 6) performing factor analysis, and 7) finalising the scale. Seven components were identified: medication-taking behaviour, nutritional care, substance use cessation, stress management, physical activity, sleep quality, and preventive behaviours. RESULTS The ATTS showed strong content validity (content validity index = 0.92) and reliability (Cronbach’s alpha = 0.894). Exploratory factor analysis identified 33 items across seven domains. Confirmatory factor analysis indicated a good model fit: χ 2 /df = 1.97, comparative fit index = 0.94, Tucker–Lewis index = 0.88, root mean square error of approximation = 0.066, and standardised root mean square residual = 0.054. CONCLUSION The ATTS is a reliable and valid tool for assessing TB treatment adherence, including both medication and lifestyle factors, with applications in clinical practice, nursing education, and research.