Evaluating a Pragmatic Strength Alternative for Frailty Measurement and Assessing Its Predictive Capacity Against Established Frailty Instruments in Rheumatoid Arthritis.

OBJECTIVE

Frailty occurs prematurely in rheumatoid arthritis (RA) and is associated with poor health outcomes. We compared the performance of four frailty instruments, including a pragmatic alternative measure using chair sit-to-stand (STS), and evaluated their abilities to predict poor health outcomes.

METHODS

Frailty was measured at baseline using four instruments: the Fried Frailty Phenotype with STS (Fried-STS), the Fried Frailty Phenotype with hand grip strength (Fried-HGS), the Veterans Affairs Frailty Index (VA-FI), and the FRAIL Scale. Outcomes collected at the one-year follow-up included category of falls (none, one, more than one), category of days hospitalized (none, one to three, more than three), and a composite outcome of fall, hospitalization, or death. Ordinal logistic or logistic regression models, adjusted for age and sex, explored the association of frailty and each outcome.

RESULTS

A total of 143 participants were included (mean ± SD age 64.5 ± 11.7 years, 73% male, and 69% White). Categorization as frail differed by instrument: Fried-STS, 17%; Fried-HGS, 15%; VA-FI, 36%; and FRAIL Scale, 20%. There was poor agreement between frailty instruments (k = 0.07-0.31) except for the Fried-STS and Fried-HGS (k = 0.62). Frailty by the Fried-STS, Fried-HGS, and FRAIL Scale was associated with falls (adjusted odds ratios [aORs] 3.83-9.54, P < 0.05). Frailty by the VA-FI was associated with days hospitalized (aOR 5.21, P = 0.017). Frailty by the Fried-STS, VA-FI, and FRAIL Scale was associated with higher odds of the composite measure of incident fall, hospitalization, or death (aORs 2.93-7.25, P < 0.05).

CONCLUSION

Each frailty measure predicted adverse health outcomes, with phenotypic and patient-reported measures predicting falls and the deficit accumulation model predicting hospitalization days. Being frail by the Fried-HGS did not predict poor outcomes as well as the other frailty instruments, including the Fried-STS.