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

Abstract

BackgroundMost 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.MethodsThis 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 ICU survival (primary outcome) and 30–90 days thereafter, duration of mechanical ventilation, and length ICU stay and of hospital stay (LOS). Nonparametric tests and regression analyses were performed.ResultsWe included 70 patients (73% male, median age 60 years). Upon admission, median BMI was 30 kg/m2, 54% were obese (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 < 0.001). Regarding clinical outcome, only low PA was associated with prolonged LOS (odds ratio = 0.83, 95% CI = 0.72–0.96; P = 0.015). Patients with optimal protein intake (>80%) during acute phase maintained significantly more FFM (2.7 kg, P = 0.047) in the late phase compared with patients who received <80%.ConclusionFFM decreased significantly during acute and late phase of illness, but we observed no association with ICU survival. Only low PA was associated with prolonged LOS. FFM wasting likely occurred because of disease severity and immobility.