Development and Validation of a Tool to Assess Determinants of Nutritional Behavior in Patients with Heart Failure Based on the Theory of Planned Behavior

Fatemeh Sadat  Alavi; Payam  Farahbakhsh; Tahereh  Dehdari

doi:10.18502/jthc.v20i3.20108

Fatemeh Sadat Alavi Student Research Committee, Iran University of Medical Sciences, Tehran, Iran.
Payam Farahbakhsh Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran.
Tahereh Dehdari Health Promotion Research Center, Iran University of Medical Sciences, Tehran, Iran.

DOI: https://doi.org/10.18502/jthc.v20i3.20108

Keywords: Heart Failure; Nutritional Behavior; Theory of Planned Behavior; Psychometrics, Instrument

Abstract

Background: Adopting healthy nutritional behavior among patients with heart failure (HF) plays a crucial role in controlling disease symptoms. Developing effective interventions requires identifying significant determinants of nutritional behavior using theoretical frameworks from behavioral sciences and validated instruments. This study aimed to develop and validate tools to assess the determinants of nutritional behavior in patients with HF based on the Theory of Planned Behavior (TPB).

Methods: A preliminary instrument with four subscales was developed based on the TPB. An instrument for measuring the nutritional behavior of patients with HF was also created. Face and content validity were assessed using qualitative and quantitative methods. The factor structure of the TPB instrument was examined using exploratory factor analysis (EFA) in a sample of 330 patients with HF. Instrument reliability was also evaluated.

Results: During face and content validity assessment, 13 items were removed from the TPB instrument, and 14 items were modified across both instruments. The EFA revealed that the 12 items measuring TPB variables loaded onto four distinct subscales: behavioral intention, attitude, perceived behavioral control, and subjective norms. The Kaiser-Meyer-Olkin measure and Bartlett test of sphericity were acceptable. These factors accounted for 87.03% of the total variance. All TPB subscales demonstrated acceptable internal consistency, as measured by Cronbach’s α. Both instruments showed satisfactory intraclass correlation coefficients.

Conclusion: The developed instruments are valid and reliable tools for assessing the determinants of nutritional behavior in patients with HF based on the TPB. They can be used for needs assessment and to develop educational interventions for this population.