Development and evaluation of frailty index for patients with systemic lupus erythematosus in China

ObjectiveTo develop and validate a frailty assessment scale tailored for patients with systemic lupus erythematosus (SLE).MethodsBased on the theory of the frailty integration model, an initial draft of the frailty index questionnaire was developed through a comprehensive literature review and a two - round Delphi expert consultation. The final version of the scale was formed through a pre - survey and a formal survey. The validity of the questionnaire was tested using content validity, structural validity, and criterion - related validity. The reliability was evaluated using Cronbach's α coefficient, split - half reliability, and test - retest reliability.ResultsThe initial item pool of the scale contained 3 dimensions and 32 items. After two rounds of Delphi expert consultations, the draft scale was refined to 21 items across 3 dimensions. Pilot testing with 50 SLE patients further reduced it to 14 items. The formal content validity Cronbach's α coefficient was 0.809, the split - half reliability was 0.745, the KMO was 0.820, and the Bartlett's test value was 2915.855 (p < 0.001). The results of exploratory factor analysis showed that, except for a few items, the correlation coefficient between the score of each item and its score in the corresponding dimension was greater than 0.4, and the overall correlation coefficient was 0.832 (p < 0.001). The optimal cutoff value for the pre - frailty stage was 28.5, and that for the frailty stage was 40.5.ConclusionThe frailty index scale developed in this study is a valid and reliable tool for assessing frailty in SLE patients in China, with potential utility in clinical and research settings.