SARC-F as a Screening Tool in Rheumatoid Arthritis: Real-World Burden of Sarcopenia Risk, Sex Differences, and Clinical Correlates

Background/Objectives: Sarcopenia is increasingly recognized as a relevant comorbidity in rheumatoid arthritis (RA), yet systematic case finding is rarely implemented in clinical practice. The SARC-F questionnaire offers a simple, validated, patient-reported tool for sarcopenia screening, but its performance in RA remains largely unexplored. We aimed to evaluate the burden of sarcopenia risk, defined by abnormal SARC-F scores (≥4), and its clinical correlates in RA compared with age- and sex-matched controls. Methods: We conducted an observational case–control study including 275 RA patients (69.5% women) aged >50 years and 300 matched controls. Clinical, laboratory, and patient-reported outcomes were recorded. Sarcopenia risk was assessed using SARC-F (cutoff ≥4). RA patients also underwent grip strength and gait speed testing. Multivariable regression analyses were used to identify independent correlates of abnormal SARC-F results. Results: A SARC-F score ≥4 was observed in 28.8% of RA patients. Compared with controls, the burden was significantly higher in women with RA (34.0% vs. 24.7%, p < 0.05) but not in men (10.7% vs. 15.0%). Within the RA cohort, abnormal SARC-F was independently associated with female sex (OR 3.14, 95% CI 1.24–7.95) and higher RAPID3 scores (OR 1.25, 95% CI 1.18–1.33). More than half of RA patients exhibited low grip strength, with partial overlap with SARC-F findings. Conclusions: The SARC-F questionnaire revealed a notable burden of sarcopenia risk in RA, particularly among women. Combined with simple grip strength testing, it offers a feasible, low-cost approach to case finding, directly applicable in routine rheumatology practice. Incorporating this strategy may enhance recognition and management of sarcopenia in RA.