RESUMEN
Objectives: The SARC-F is a validated questionnaire for the screening of sarcopenia in an older population. However, the clinical relevance of this self-reported questionnaire in patients with cognitive problems is questionable. This study aims to validate the SARC-F-Proxy as an alternative screening tool for sarcopenia in patients with cognitive impairment. Methods: This cross-sectional study included hospitalised community-dwelling older adults aged 60 years or older with confirmed cognitive impairment. Three SARC-F questionnaires were completed: one by patients, one by informal caregivers and one by formal caregivers. Muscle strength, mass and physical performance were measured by handgrip strength, anthropometric measurements, and gait speed respectively. The recently updated EWGSOP2 diagnostic criteria were used as the "gold standard" for diagnosis of sarcopenia. Results: The prevalence of sarcopenia using SARC-F-Proxy was 75.4% for SARC-F-Proxy-Formal caregiver and 66% for SARC-F-Proxy-Informal caregiver. SARC-F-Proxy had high sensitivity (85.9% for SARC-F-Proxy-Formal caregiver and 77% for SARC-F-proxy-informal caregiver) and low specificity (46.5% for SARC-F-Proxy-Formal caregiver and 54.7% for SARC-F-Proxy-Informal caregiver). Conclusions: the proxy-reported SARC-F questionnaire can be applied as a surrogate for the SARC-F in the screening of sarcopenia in hospitalised community-dwelling older people with known or suspected cognitive impairment. Second, the results in this study suggest a higher reliability when the proxy-reported questionnaire is performed by the formal caregiver.