Psychometric Properties of the Treatment Adherence Questionnaire in Hemodialysis Patients: A Cross-Sectional Study Using Social Cognitive Theory

Abstract

Background and Aims Effective management of hemodialysis patients is often hindered by low treatment adherence, underscoring the need for valid, theory-driven assessment tools. This study had two aims: (1) to develop a questionnaire based on Social Cognitive Theory for assessing treatment adherence behaviors among hemodialysis patients and (2) to evaluate its validity and reliability.Methods This methodological study employed a cross-sectional design. An initial pool of 57 items was generated through an extensive literature review and expert consultation, followed by cultural adaptation and expert panel review. The study was conducted among 181 hemodialysis patients in Isfahan, Iran, to examine face, content, and construct validity, as well as internal consistency reliability. Content validity was assessed using the Content Validity Index (CVI) and Content Validity Ratio (CVR). Construct validity was evaluated using exploratory and confirmatory factor analyses, and internal consistency was assessed using Cronbach's alpha.Results The final questionnaire comprised 30 items across six domains: self-efficacy, outcome expectations, social support, communication skills, disease acceptance, and self-regulation. Content validity indices were satisfactory (mean CVI = 0.92, mean CVR = 0.87), and internal consistency was high (Cronbach's alpha = 0.88). Exploratory factor analysis revealed a six-factor structure that explained 57.33 of the total variance, and confirmatory factor analysis demonstrated an acceptable model fit (chi 2/df = 1.37, CFI = 0.91, RMSEA = 0.032). Among the SCT constructs, self-regulation showed the strongest association with treatment adherence behaviors.Conclusion The ESRD Treatment Adherence Questionnaire based on Social Cognitive Theory (ESRD-TAQ-SCT) demonstrated strong validity and reliability. This culturally adapted instrument provides a practical, theory-driven tool for assessing treatment adherence and informing behavioral interventions among hemodialysis patients.