Association between fat‐free mass and survival in critically ill patients with COVID‐19: A prospective cohort study

Background Most critically ill patients with COVID‐19 experience malnutrition and weight loss associated with negative clinical outcomes. Our primary aim was to assess body composition during acute and late phase of illness in these patients in relation to clinical outcome and secondary to tailored nutrition support. Methods This prospective cohort study included adult critically ill patients with COVID‐19. Body composition (fat‐free mass [FFM] [exposure of interest], fat mass [FM], skeletal muscle mass [SMM], and phase angle [PA]) was determined with multifrequency bioelectrical impedance analyses in the acute and late phase. Nutrition support data were collected simultaneously. Clinical outcome was defined as intensive care unit (ICU) survival (primary outcome) and 30–90 days thereafter, duration of mechanical ventilation, and length of ICU stay and length of hospital stay (LOS). Nonparametric tests and regression analyses were performed. Results We included 70 patients (73% male, median age 60 years). Upon admission, median BMI was 30 kg/m2, 54% had obesity (BMI > 30 kg/m2). Median weight change during ICU stay was −3 kg: +3 kg FM and −6 kg FFM (−4 kg SMM). Body composition changed significantly (P 80%) during acute phase maintained significantly more FFM (2.7 kg, P = 0.047) in the late phase compared with patients who received