Validity and reliability study of dietary sodium restriction questionnaire

This research was conducted methodologically to assess the Turkish adaptation, validity, and reliability of the Dietary Sodium Restriction Questionnaire (DSRQ) The study population includes individuals diagnosed with heart failure (HF) who were advised to limit their dietary sodium intake and who were hospitalized in the Cardiology and Cardiovascular Surgery clinic in the Hospital of Medical Faculty of Ege University or those who were admitted to the cardiology clinic (n = 8000). The sampling of the research consisted of individuals who were admitted to the Hospital of Medical Faculty of Ege University between March and November 2017, received inpatient or outpatient treatment, had orientation of individual, place and time, diagnosed HF, had been advised to limit their sodium intake, and volunteered to participate in the study (n = 300). Data were collected using the Introductory Information Form, the DSRQ, and the Beliefs Scale on Compliance to Diet. To ensure the validity of the language used on the forms, the scale was translated into Turkish and then re-translated as the first stage of the validity process. Once language validity was confirmed, the scale was offered to the expert for content validation. Expert opinions were evaluated using the Davis technique. The Content Validity Ratio and the Content Validity Index were above 0.80 for all the items according to expert opinions. After preliminary application of the scale, the data were collected via face-to-face interview. The answers given by the participants were marked by the researcher. To validate the content of the scale of the scale, the Exploratory and Confirmatory Factor Analysis (CFA) method was used. The scale was classified into three factors in accordance with its original structure according to the Principal Component Analysis. However, the items were collected under different factors. CFA compliance index values were appropriate for the scope validity (x2/df = 2.02, RMSEA = 0.07, CFI = 0.94, NFI = 0.93, NNFI = 0.93, SRMR = 0.05, GFI = 0.94, AGFI = 0.92). To assess the criterion validity of the scale, the Beliefs Scale on Compliance to Diet and coefficients of the correlation were examined, and a significant correlation was found between them. It has been concluded, as a result of these findings, that the DSRQ is a valid measurement tool for Turkish society. Item-total score correlations were first investigated for the reliability study of the DSRQ. Their values were found between 0.30 and 0.84, which were statistically significant. A t-test was conducted to determine the item distinction power and the results showed that there was a statistically significant difference between the groups. Furthermore, the items were determined to have significant distinction power, so no item was excluded (p <0.001). The Cronbach alpha value of the scale was 0.92 and the Cronbach alpha sub-scale values ranged between 0.83 and 0.97. To determine the time-invariance quality of the DSRQ, the scale was re-administered to 50 individuals 2 weeks after the first application and the relationship between the two measures was assessed. When the first and last measurements were examined, there was a significant positive correlation between sub-scale total score and scale total score correlations (p < 0.001). As a result of these findings, the DSRQ was determined to be a reliable measurement tool for Turkish society. It is recommended that this scale be applied by nurses and other health professionals in primary and secondary healthcare units to patients who were diagnosed HF and received sodium-limited dietary advice to assess their compliance to the diet. Furthermore, the validity and reliability of the scale for the sample groups who were advised to limit their dietary sodium intake and with different disease diagnoses should be assessed.