Comparison of two frailty definitions in women with systemic lupus erythematosus.

Objectives: Frailty is a risk factor for adverse health in SLE. The Fried phenotype (FP) and the SLICC Frailty Index (SLICC-FI) are common frailty metrics reflecting distinct approaches to frailty assessment. We aimed to (1) compare frailty prevalence according to both metrics in women with SLE and describe differences between frail and non-frail participants using each method and (2) evaluate for cross-sectional associations between each metric and self-reported disability.

Methods: Women aged 18-70 years with SLE were enrolled. FP and SLICC-FI were measured, and agreement calculated using a kappa statistic. Physician-reported disease activity and damage, Patient Reported Outcome Measurement Information System (PROMIS) computerized adaptive tests, and Valued Life Activities (VLA) self-reported disability were assessed. Differences between frail and non-frail participants were evaluated cross-sectionally, and the association of frailty with disability was determined for both metrics.

Results: Of 67 participants, 17.9% (FP) and 26.9% (SLICC-FI) were frail according to each metric (kappa = 0.41, P < 0.01). Compared with non-frail women, frail women had greater disease damage, worse PROMIS scores, and greater disability (all P < 0.01 for FP and SLICC-FI). After age adjustment, frailty remained associated with a greater odds of disability [FP: odds ratio (OR) 4.7, 95% CI 1.2, 18.8; SLICC-FI: OR 4.6, 95% CI 1.3, 15.8].

Conclusion: Frailty is present in 17.9-26.9% of women with SLE. These metrics identified a similar, but non-identical group of women as frail. Further studies are needed to explore which metric is most informative in this population.