Arthritis Care Res (Hoboken). 2026 Mar 9. doi: 10.1002/acr.80036. Online ahead of print.
ABSTRACT
OBJECTIVE: We aimed to construct and evaluate the first laboratory-based frailty index (FI-Lab) for predicting adverse outcomes in systemic lupus erythematosus (SLE) and to compare its predictive ability to that of an existing clinical frailty index (FI).
METHODS: We used data from a single-centre prospective cohort of adult SLE patients whose baseline visit occurred between 2010 and 2019. A 30-item FI-Lab was constructed by adapting an existing list of FI-Lab variables. Cox proportional hazards regression examined the association between baseline FI-Lab scores and all-cause mortality, while negative binomial regression evaluated the association with organ damage accrual. We compared the performance of multivariable models containing the FI-Lab and/or SLICC-FI as predictor variables using AIC, Harrell’s C-statistic, and pseudo-R2 values.
RESULTS: Among 283 patients (89% female; mean age 47.7 years), 97 were classified as frail at baseline (FI-Lab >0.21). Frail individuals had increased mortality risk [Hazard ratio (HR) 3.71; 95% confidence interval (CI) 1.82-7.54] and a higher rate of organ damage accrual during follow-up [Incidence rate ratio (IRR) 2.26; 95% CI 1.59-3.22] compared to non-frail patients. The FI-Lab remained significantly associated with mortality risk after multivariable adjustment. While both indices were significant baseline predictors of organ damage accrual during follow-up, the multivariable model containing both FIs outperformed models containing either index alone.
CONCLUSION: An FI constructed exclusively from routinely collected laboratory variables can measure frailty and predict adverse outcomes in SLE. It may serve as a convenient screening tool to detect subclinical frailty and promote early risk mitigation in this population.
PMID:41801062 | DOI:10.1002/acr.80036
