Body Composition Analysis as a Predictor of Prognosis for Patients With Acute Kidney Injury Requiring Kidney Replacement Therapy

The aim of this study is to investigate the association between body composition, measured by bioelectrical impedance analysis, and outcomes in patients with acute kidney injury (AKI) receiving kidney replacement therapy (KRT).Patients with severe AKI treated with KRT in our hospital between September 2016 and August 2018 were enrolled. These patients were assessed by body composition analysis before KRT, and on the 3rd day and the 7th day after initiation of KRT. The predictors included lean tissue index (LTI), fat tissue index, and body cell mass index (BCMI). The association between all-cause mortality and predictors was analyzed using Cox regression.A total of 152 patients were included in this study, with a 28-day mortality of 46.7% and 1-year mortality of 60.5%. LTI (adjusted hazard ratio per standard deviation: 0.37; 95% confidence interval = 0.21-0.66, P < .001) and BCMI (adjusted hazard ratio per standard deviation: 0.37; 95% confidence interval = 0.21-0.67, P < .001) on day 7 after initiation of KRT, rather than before KRT, were associated with mortality during follow-up. LTI and BCMI before KRT were associated with 28-day mortality rather than 1-year mortality.LTI and BCMI before KRT were associated with short-term prognosis, and those on day 7 after KRT initiation were associated with intermediate mortality in patients with AKI requiring KRT.