Development and Validation of a Scale to Measure Fear of Activity in Patients With Coronary Artery Disease (Fact-CAD)

Abstract

Objective

To develop and validate a scale to measure fear of activity in patients with coronary artery disease.

Design

Psychometric study.

Setting

Outpatient cardiology clinics.

Participants

The scale was applied to patients who had myocardial infarction, coronary artery bypass grafting, or percutaneous coronary intervention within the last 12 months (N=250).

Interventions

A scale for fear of activity in patients with coronary artery disease (Fact-CAD) was created through semistructured focus group interviews with patients. Face and content validity of Fact-CAD was verified.

Main Outcome Measures

Psychometric analysis included model fit, unidimensionality, reliability, local dependency, differential item functioning, and external construct validity. Analyses were performed using the Rasch Analysis Model.

Results

Fact-CAD scale was a reliable (high Person Separation Index of 0.89) and valid (unidimensional, no misfit, local independency supported, no residual correlations) measure of fear of activity. Three items showed differential item functioning according to employment status, marital status, and angina pectoris, which were not assigned as real item bias by experts and remained in the model.

Conclusion

Fact-CAD was supported by Rasch analysis as a psychometrically valid scale to evaluate fear of activity in patients with coronary artery disease.