Objectives: Frailty is a topic that is gaining more and more interest in rheumatology. The aims of this study were to develop and preliminarily validate a frailty index dedicated to rheumatoid arthritis (RA) called the Comprehensive Rheumatologic Assessment of Frailty (CRAF).
Methods: Ten major frailty domains of CRAF were identified: nutritional status, weakness, falls, comorbidity, polypharmacy, social activity, pain, fatigue, physical function, and depression. Convergent validity was evaluated correlating the scores of the CRAF with the Frailty Instrument for Primary Care of the Survey of Health, Ageing and Retirement in Europe (SHARE-FI). Discriminant validity was assessed using receiver operating characteristic (ROC) curve analysis. Multivariate logistic regression model procedure was used to assess the relative contribution of the individual determinants on the CRAF.
Results: Among the 219 RA patients, 79 (36.1%) were defined as non-frail (CRAF ≤0.12), 63 (28.8%) mild frail (0.12 <CRAF ≤0.24), 34 (15.5%) moderate frail (0.24 <CRAF ≤0.36), and 43 (19.6%) severe frail (CRAF >0.36). In testing for convergent validity, a significant correlation was found between CRAF and SHARE-FI (p <0.0001). The discriminatory power of CRAF was higher than those of the SHARE-FI (difference between areas under the ROC curves=0.0853± 0.0282. Variables associated with frailty at the multivariate analysis were advanced age and high disease activity (both at p<0.0001).
Conclusions: The CRAF demonstrated a robust validity and good discriminant accuracy. Implementation of the frailty assessment into the routine rheumatological practice could represent a major advance in RA care.