Psychometric Properties of an Instrument to Determine the Factors Affecting Treatment Adherence Among Patients Receiving Hemodialysis in Sri Lanka.

Nonadherence is a widespread problem among patients receiving hemodialysis, while contributing factors are underexplored due to lack of a validated instrument. The study aimed to develop and validate a new disease-specific instrument determining the factors affecting treatment adherence behaviors among patients receiving hemodialysis in a Sri Lankan hospital. The content validation process using a modified Delphi technique suggested 42-item instrument with an average Item-level Content Validity Index (I-CVI) of 0.94. Subsequent principal component analysis (PCA) revealed 5 components with 17 items (patient-centered psychological and physical factors, factors associated with health care, hemodialysis therapy-related factors, socioeconomic factors, and factors associated with the continuity of the treatment), explaining 67.24% total variance. The reliability estimate based on Mislevy and Bock for each component greater than 0.8 and overall standardized Cronbach's alpha of 0.605, indicated acceptable internal consistency reliability. Root mean square residual (RMSR) and weighted root mean square residual (WRMR) indices of 0.084 and 0.059, respectively, indicated acceptable model fit. The final 17-item instrument provides a valid measure for the factors affecting treatment adherence behaviors of the patients receiving hemodialysis in a Sri Lankan hospital.