Evaluating the Dimensionality and Reliability of the Thai Self-Care of Hypertension Inventory Version 2.0

Self-care is essential for hypertensive individuals to promote optimal health and illness treatment. We developed the Thai Self-Care of Hypertension Inventory (SC-HI) version 2.0 from the original US version using a multi-stage approach for cross-cultural adaptation. Scales previously studied outside a US context had different dimensions and factor solutions. Therefore, we examined the Thai SC-HI's factorial validity, construct validity, and internal reliability within a Thai context.

We administered a cross-sectional survey with hypertensive patients in 10 primary care settings, and conducted exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) on two sets of separate samples from each of five sites to examine the model's factorial validity and construct validity. We estimated scale reliability with Cronbach's alpha and McDonald's omega coefficients.

Participants were predominantly female, older adults, with mean age 66 years (SD = 11.94; range 36-97 years). The self-care maintenance scale had three factors and demonstrated good fit when the error covariances were respecified. The two-factor self-care management scale had different factorial solutions compared to previous models. The CFA result showed good fit indices for the Thai, original US, and Brazilian models. The self-care confidence scale was unidimensional, with partially supported fit indices that improved after we respecified the error covariances. Reliability coefficients estimated by difference methods were nearly equal: slightly lower than desired for self-care maintenance (.68-.70) and inadequate for self-care management (.62-.65); self-care confidence reliability was adequate (.89-.90).

The Thai SC-HI has good psychometric characteristics and reflects the original instrument's theoretical basis.