Operationally Defined Sarcopenia Phenotype Among Older Egyptian Outpatients: A Descriptive Cross-Sectional Study

Background/Objectives: Sarcopenia can compromise mobility and self-care. This study estimated the prevalence of an operationally defined sarcopenia phenotype among older Egyptian outpatients and described characteristics relevant to nursing assessment; Orem's Self-Care Deficit Nursing Theory framed interpretation but was not tested. Methods: This cross-sectional study consecutively recruited 320 adults aged ≥60 years from outpatient clinics at four randomly selected public hospitals in El-Beheira Governorate (August 2024-January 2025). The operational definition, based on the EWGSOP 2010 framework, combined calf circumference <31 cm as a pragmatic muscle-mass proxy with low handgrip strength and/or gait speed ≤ 0.8 m/s. Nutrition and functional independence were assessed using the BMI-based MNA-SF and Lawton-Brody IADL scale. Primary analyses comprised descriptive summaries and Wilson 95% confidence intervals; exploratory Firth-penalized logistic regression models adjusted for age and sex were sensitivity analyses. Results: The phenotype was present in 109/320 participants (34.1%; 95% CI, 29.1-39.4%). Prevalence was 2.7% at ages 60-74 years, 16.8% at 75-84 years, and 91.6% at ≥85 years. Nutritional vulnerability, IADL dependence, food insecurity, polypharmacy, and recent hospitalization were descriptively more common among participants meeting the definition. Adjusted models retained several associations but yielded an unstable reversed nutritional estimate and wide confidence intervals. Conclusions: The operational phenotype identified a clinically vulnerable outpatient subgroup relevant to nursing and interdisciplinary assessment. The proxy-based definition, clinic sampling, extreme age imbalance, and cross-sectional design preclude confirmation of sarcopenia and independent-association, prognostic, or causal inference.