Objective: To construct a self-reported outcome scale for diabetic foot patients, and to test its reliability and validity.
Methods: Through literature reading and interviews with 30 patients, a pool of scale items was formed. The items were classified and sorted out according to the expected scale structure framework. After two rounds of expert consultation and a small range of test dressing, the initial scale was formed. Through the investigation of 85 patients with diabetic foot, item differentiation analysis, correlation analysis and exploratory factor analysis were used to screen the items. Cronbach’s α coefficient, retest reliability and content and structure validity analysis were used to determine the feasibility and validity of the scale.
Results: The final scale included 4 first-level items and 22 second-level items. The critical ratio method showed that the scores of each item in the high group and the low group were significantly different (P < 0.05). Correlation analysis showed that the correlation coefficient between each item and the total score was 0.431 to 0.829; The content validity index of the scale was 0.91, the exploratory factor analysis identified three common factors, and the cumulative variance contribution rate was 75.381%. The confirmatory factor analysis showed that the model fit well. The Cronbach’s α coefficient of the scale was 0.934 and the retest reliability coefficient was 0.926.
Conclusion: The self-reported outcome scale for diabetic foot patients has good reliability and validity, and can be used to investigate the health status of diabetic foot patients and evaluate the therapeutic effect.
Keywords: diabetic foot, patient-reported outcome, scale, reliability, validity