Malnutrition, Sarcopenia Risk Screening, and Muscle Function in Subacute Stroke Survivors Admitted to Long-Term Care Rehabilitation Units

Background/Objectives: Malnutrition and muscle weakness are prevalent after stroke. We assessed nutritional status, evaluated low handgrip strength (HGS) on the non-affected side, and compared Strength, Assistance with walking, Rise from a chair, Climb stairs, and Falls (SARC-F) and canonical SARC-F combined with calf circumference (SARC-CalF) classifications during subacute institutional rehabilitation. Methods: This cross-sectional study included 86 subacute stroke survivors across four long-term care units (mean age 72.5 ± 11.4 years; 1.0–4.0 months post-stroke). Nutritional assessment used the Mini Nutritional Assessment Full Form (MNA-FF) and Global Leadership Initiative on Malnutrition (GLIM) criteria. Canonical SARC-CalF incorporated sex-specific calf circumference cutoffs (≤34 cm in men; ≤33 cm in women). Non-affected-side HGS was classified by EWGSOP2 thresholds. Multivariable models were adjusted for age, sex, and time since stroke, including Firth-penalized logistic sensitivity analyses. Results: GLIM-defined malnutrition and low HGS affected 75.6% and 67.4% of participants, respectively. SARC-F and SARC-CalF positivity rates were 88.4% and 81.4%, demonstrating fair agreement (κ = 0.28; exact McNemar p = 0.210), which persisted in participants aged ≥65 years (κ = 0.30). Both scores correlated inversely with HGS (rho = −0.399 and −0.387; p < 0.001), while MNA-FF correlated positively (r = 0.47; p < 0.001). Adjusted HGS coefficients were −5.90 kg (95% CI −11.22 to −0.59; p = 0.030) for SARC-F and −2.54 kg (95% CI −7.02 to 1.95; p = 0.264) for SARC-CalF. Firth-adjusted GLIM odds ratios were 13.75 (95% CI 2.76–99.21) and 3.21 (95% CI 0.95–11.00), respectively. Conclusions: Malnutrition and low HGS were frequent despite relatively preserved mean body mass index. SARC-F and SARC-CalF yielded discordant classifications. Because neurological severity and muscle quantity were not directly assessed, differing weightings of functional limitations and anthropometry may partly explain this pattern, but this interpretation remains hypothesis-generating without establishing confirmed sarcopenia or distinct causal mechanisms.