Psychometric Testing of the Indonesian Version of Dietary Sodium Restriction Questionnaire Among Patients with Hypertension

Abstract

Purpose: The purpose of this research was to test the validity and reliability of the Indonesian version of the Dietary Sodium Restriction Questionnaire (DSRQ-I) among patients with hypertension. Methods: The cross-sectional study enrolled hypertensive patients from a cardiac outpatient department in Indonesia using convenience sampling. Eligible patients received a demographic questionnaire and DSRQ-I during a one-month period of data collection. Content and construct analysis examined the validity, whereas internal consistency assessment checked reliability. Participation required 10e 15 minutes on average. Results: One hundred thirty-five patients participated: mostly females (54.1%) and married (82.9%) with mean age of 58.18 ± 10.44 years. The item of content validity index was .97, and subscale content validity index was .81 for DSRQ-I. The KaisereMeyereOlkin test gave a value of .83, indicating adequate sampling, and the Bartlett's test of sphericity reached significant result (p < .001). The principal component analysis indicated three components, with 64.2% explaining variance, including perceived behavioral control (35.5%), attitude (19.3%), and subjective norm (9.4%). Confirmatory factor analysis produced a parsimonious model on the three-factor outcome by removing a single item. The indices of good fit model was achieved at c2/df ¼ 2.17, goodness fit index ¼ .85, root mean square error of approximation ¼ .09, standardized root mean square means ¼ .07, and Bentler comparative fit index ¼ .90 (p < .001). Cronbach's alpha coefficients for attitude, subjective norm, and perceived behavioral control were .85, .87, and .85, respectively. All interitem and item-total correlations indicated adequate outcome and acceptable result. Consequently, 15 items were determined reliable measurement and included in the final version of DSRQ-I. Conclusion: The DSRQ-I is a valid and reliable instrument to measure facilitators and barrier of sodium restriction among hypertensive patients in Indonesia."