Validity and reliability of the Dietary Sodium Restriction Questionnaire (DSRQ)

The Dietary Sodium Restriction Questionnaire (DSRQ) was designed to assess attitudes and behaviors of patients with heart failure (HF) related to following a low-sodium diet. Recently, it has been translated and culturally adapted for use in Brazil. However, further validation of the instrument is required before it can be used in the management of patients with HF in Brazil.

To test the reliability and validity of the Brazilian version of the DSRQ.

Face and content validity were assessed by a panel of experts. Construct validity was tested using exploratory and confirmatory factor analysis. Reliability was tested using Cronbach's alpha to assess the internal consistency of the instrument.

A total of 206 systolic HF outpatients were assessed (mean age, 60.4 ± 11.9 years). Face and content validity analysis showed equivalence between the Brazilian version and the original instrument. In the exploratory factor analysis, the principal component analysis (PCA) yielded four factors with eigenvalues greater than 1. Three models were tested in the confirmatory factor analysis, and the three-factor model resulting from the PCA showed the best fit, accounting for 49% of the variance. Alpha values obtained for the attitude/subjective norm, perceived behavioral control, and dependent behavior subscales were 0.71, 0.67, and 0.79, respectively.

Our results suggest that the final validated Brazilian version of the DSRQ is a valid and reliable tool for measuring attitudes and behaviors related to following a low-sodium diet in Brazilian patients with HF.