Development and validation of measurement tools to assessing the determinants of nutritional behavior based on theory of planned behavior variables among patients with heart failure

An instrument to measure the determinants of nutritional self-care behavior in patients with heart failure

Abstract

Background: Adopting healthy nutritional behavior in patients with Heart Failure (HF) can play a crucial role in controlling symptoms of the disease. To develop effective interventions, it is recommended to recognize significant determinants of nutritional behavior based on theoretical frameworks in behavioral sciences and utilize valid instruments. The aim of this study was to develop and validate measurement tools for assessing the determinants of nutritional behavior among patients with HF based on the Theory of Planned Behavior (TPB) variables.

Methods: In this psychometrics study, a preliminary instrument based on the TPB with five subscales was created. Additionally, an instrument for measuring the nutritional behavior of HF patients was developed. The face validity and content validity of the instruments were assessed using both quantitative and qualitative methods. The factor structure of the instrument for assessing TPB variables was examined through Exploratory Factor Analysis (EFA) using a sample of 330 patients with HF. Furthermore, the reliability of the instruments was evaluated.

Results: In the stages of face validity and content validity assessment, 13 items were removed from the TBP instrument, and 14 items were modified in the two instruments. The EFA revealed that the 12 items of the TPB variables could be classified into 4 subscales, namely behavioral intention, attitude, and perceived behavioral control. The results of the EFA indicated that the Kaiser-Meyer-Olkin and Bartlett’s test of sphericity of the instrument were acceptable. These factors accounted for 87.03% of the variance. The TPB instrument subscales demonstrated acceptable levels of reliability, as indicated by Cronbach's alpha. Both instruments had acceptable levels of intraclass correlation coefficient.

Conclusions: The results showed that the developed instruments were two valid and reliable tools for assessing the determinants of adopting nutritional behavior among patients with HF, utilizing TPB variables. These instruments can be used in conducting needs assessments and developing education intervention efforts for patients with HF.