Changes in body composition in the year following critical illness: A case-control study

PURPOSE: To measure changes in dual x-ray absorptiometry (DXA) derived body composition in Intensive Care Unit (ICU) survivors in the year following discharge and compare to population controls. MATERIALS AND METHODS: Using prospective observational data changes in hip and spine DXA estimated lean and fat mass between ICU discharge and 1-year follow-up were calculated and compared with age-sex-height matched controls from the Geelong Osteoporosis Study via multivariable linear regression. RESULTS: Sixty-four participants were included, with median age 68.8 yr [IQR 60.8, 74.6], ICU length of stay 6.5 d [IQR 4, 9] and duration of mechanical ventilation 87 h [IQR 47, 143]. ICU survivors demonstrated greater annual increases in lean (+0.92 kg; 95%CI 0.67 to 1.18, p < 0.01) and fat mass (+2.50 kg, 95%CI 1.94 to 3.05; p < 0.01) than controls. At 1-yr follow-up, the ICU group had lower lean mass (-0.96 kg, 95%CI -1.91 to -0.01; p = 0.047) and greater fat mass (6.79 kg, 95%CI 4.55 to 9.03; p < 0.001). CONCLUSIONS: Mechanically ventilated adult ICU patients gained lean mass in the year following critical illness but did not reach the level of matched population-based peers. Understanding the factors associated with, and effect of increasing muscle mass and reducing fat mass in the year after critical illness requires further investigation.