**Background**
Frailty is a multidimensional syndrome of decreased physiological reserve and increased vulnerability to stressors, leading to adverse outcomes such as falls, disability, and mortality. In immune-mediated rheumatic diseases (IMRDs) like rheumatoid arthritis (RA), spondyloarthritis, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and vasculitis, chronic inflammation (inflammaging) and sarcopenia are considered biological substrates of frailty. The prevalence of frailty in the general population over 65 years ranges from 7–10% up to 40% in octogenarians. In IMRDs, frailty is even more prevalent and associated with worse quality of life, morbidity, and mortality. This narrative review aims to quantitatively synthesize published literature on frailty prevalence in IMRDs and summarize current evidence on the most widely used frailty screening tools.
**Methods**
The authors conducted a narrative review of the literature, summarizing studies on frailty in IMRDs including RA, psoriatic arthritis (PsA), ankylosing spondylitis (AS), SLE, SSc, and ANCA-associated vasculitis (AAV). They describe the two main conceptual models of frailty: Fried’s physical frailty phenotype (weight loss, exhaustion, slow gait speed, weakness, low physical activity) and Rockwood’s cumulative deficit method (Frailty Index, FI). They also review several screening tools: Fried’s phenotype, SHARE-FI, FI of cumulative deficits, Groningen Frailty Indicator (GFI), Edmonton Frail Scale (EFS), Comprehensive Geriatric Assessment (CGA), Tilburg Frailty Indicator (TFI), PRISMA-7, QFrailty score, and the newly developed Comprehensive Rheumatologic Assessment of Frailty (CRAF) index. The CRAF index includes 10 domains (nutritional status, weakness, falls, comorbidity, polypharmacy, social activity, pain, exhaustion, physical function, depression) scored from 0 to 1, with cut-offs: 0–0.12 = no frailty; >0.12–0.24 = mild; >0.24–0.36 = moderate; >0.36 = severe frailty.
**Key Results**
- In SLE, a study of 152 women found 20% frail (≥3 Fried criteria) and 50% pre-frail (1–2 criteria). Frail patients had worse physical function and cognitive impairment, and mortality risk was almost six times higher than robust patients.
- In the SLICC cohort (1682 SLE patients), 27.1% were frail (FI >0.21). Nearly 20% of SLE patients <30 years old were frail, compared to ~2.0% in the general population of the same age.
- In SSc-ILD, frailty prevalence was 55% using a 42-item FI. Dyspnea had the strongest association with frailty (r=0.62, p<0.001).
- In AAV patients ≥65 years, frailty scores (HR 1.90), age (HR 1.13), and very high baseline CRP (HR 5.71) were independently associated with increased mortality. Five-year survival was 47% in the more frail group vs. 90% in the less frail group.
- Sarcopenia prevalence: ~30% in Japanese RA patients; 20.7% in SSc; 34.3% in AS (by EWGSOP criteria).
- Inflammatory markers: CRP, IL-6, and TNFα are elevated in frail individuals. In the Cardiovascular Health Study, CRP was an independent predictor of frailty over 9 years. IL-6 >5 pg/mL was linked to muscle weakness and reduced handgrip strength.
- The CRAF index was developed via Delphi method with 39 experts; variables with mean score >3.0 from >80% of experts were included.
**Clinical Implications**
Frailty is a significant and underrecognized issue in IMRDs, contributing to poor outcomes including disability, hospitalization, and mortality. Screening for frailty using validated tools (e.g., Fried phenotype, FI, CRAF) can identify vulnerable patients who may benefit from targeted interventions such as resistance training, nutritional support, and management of inflammation. The CRAF index, specifically designed for RA, may improve prognostication and guide personalized care. Future research should focus on standardizing frailty definitions in IMRDs and testing interventions to prevent or reverse frailty.