Chia-Ter Chao1, Vin-Cent Wu, Hung-Bin Tsai, Che-Hsiung Wu, Yu-Feng Lin, Kuan-Dun Wu, Wen-Je Ko. 1. *Department of Traumatology and †Division of Nephrology, Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University; ‡Division of Nephrology, Buddhist Tzu Chi General Hospital; and §National Taiwan University Hospital Study Group on Acute Renal Failure, Taipei, Taiwan.
Abstract
BACKGROUND: Acute kidney injury (AKI) frequently occurs in hospitalized patients, particularly in the elderly. However, studies on outcome-modifying factors in geriatric patients with AKI are absent, especially the influence of body mass index (BMI). METHODS: We performed a retrospective analysis of a prospectively collected multicenter observational cohort, which enrolled elderly (≥65 years) who developed AKI after major surgery in the intensive care units. We analyzed in-hospital mortality within BMI category utilizing Cox proportional hazard regression analysis and generalized additive modeling. RESULTS: Data of a total of 2,015 postoperative elderly patients were retrieved and analyzed. Generalized additive modeling showed that elderly AKI patients with a BMI between 21 and 31 kg/m(2) ("normal") had a lower mortality risk than those with a BMI of less than 21 kg/m(2) ("underweight") or 31 kg/m(2) or greater ("obese"). Both "underweight" and "obese" individuals had a greater risk of mortality compared with patients with "normal" BMI. CONCLUSIONS: The U-shaped association of BMI with hospital mortality in geriatric AKI patients contains a widened base and a shifted nadir comparing with chronic dialysis and other AKI patients. This finding is interesting and warrants our attention.
BACKGROUND:Acute kidney injury (AKI) frequently occurs in hospitalized patients, particularly in the elderly. However, studies on outcome-modifying factors in geriatric patients with AKI are absent, especially the influence of body mass index (BMI). METHODS: We performed a retrospective analysis of a prospectively collected multicenter observational cohort, which enrolled elderly (≥65 years) who developed AKI after major surgery in the intensive care units. We analyzed in-hospital mortality within BMI category utilizing Cox proportional hazard regression analysis and generalized additive modeling. RESULTS: Data of a total of 2,015 postoperative elderly patients were retrieved and analyzed. Generalized additive modeling showed that elderly AKI patients with a BMI between 21 and 31 kg/m(2) ("normal") had a lower mortality risk than those with a BMI of less than 21 kg/m(2) ("underweight") or 31 kg/m(2) or greater ("obese"). Both "underweight" and "obese" individuals had a greater risk of mortality compared with patients with "normal" BMI. CONCLUSIONS: The U-shaped association of BMI with hospital mortality in geriatric AKI patients contains a widened base and a shifted nadir comparing with chronic dialysis and other AKI patients. This finding is interesting and warrants our attention.