To develop and validate two parallel versions of the Heart Disease Fact Questionnaire-Rheumatoid Arthritis (HDFQ-RA), a modified and RA-specific version of the HDFQ.
The questionnaire was composed of generic questions from the original HDFQ with additional RA-specific questions added. Cognitive interviewing was performed and the questionnaire piloted to generate two parallel questionnaires. For psychometric validation, 130 patients with RA completed the questionnaires at baseline and 2 weeks later.
Parallel form reliability of both questionnaires was established; the median score for both questionnaires was 9/13 with no statistical difference in scores. Kuder-Richardson-20 formula was 0.65 and 0.67 for both questionnaires. Test-retest stability showed constant median scores of 9/13 and no statistical difference in scores between baseline and follow-up. Known groups comparison revealed that patients who had self-educated themselves about heart disease, or who were taking CVD medications, had significantly higher scores on the questionnaires.
The HDFQ-RA is an appropriate tool for application in clinical and research settings, e.g., assessing novel educational interventions or tracking participants' progress on an education course.
The two parallel forms of the HDFQ-RA have been shown to be equivalent measures of CVD knowledge and evidence supporting their reliability and validity is presented.