title: Body mass index is inversely associated with mortality in patients with acute kidney injury undergoing continuous renal replacement therapy.
abstract: BACKGROUND
  Many epidemiologic studies have reported on the controversial concept of the obesity paradox. The presence of acute kidney injury (AKI) can accelerate energy-consuming processes, particularly in patients requiring continuous renal replacement therapy (CRRT). Thus, we aimed to investigate whether obesity can provide a survival benefit in this highly catabolic condition.
  
  
  METHODS
  We conducted an observational study in 212 patients who had undergone CRRT owing to various causes of AKI between 2010 and 2014. The study end point was defined as death that occurred within 30 days after the initiation of CRRT.
  
  
  RESULTS
  Patients were categorized into three groups according to tertiles of body mass index (BMI). During ≥30 days after the initiation of CRRT, 39 patients (57.4%) in the highest tertile died, as compared with 58 patients (78.4%) in the lowest tertile (P= 0.02). In a multivariable analysis adjusted for cofounding factors, the highest tertile of BMI was significantly associated with a decreased risk of death (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.37-0.87;P= 0.01). This significant association remained unaltered for 60-day (HR, 0.64; 95% CI, 0.43-0.94;P= 0.03) and 90-day mortality (HR, 0.66; 95% CI, 0.44-0.97;P= 0.03).
  
  
  CONCLUSIONS
  This study showed that a higher BMI confer a survival benefit over a lower BMI in AKI patients undergoing CRRT.
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Hyoungnae
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Joohwan
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Changhwan
authors.initials: C
authors.lastname: Seo
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Misol
authors.initials: M
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Min-Uk
authors.initials: MU
authors.lastname: Cha
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Jung
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Jhee
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Seohyun
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Hae-Ryong
authors.initials: HR
authors.lastname: Yun
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Youn Kyung
authors.initials: YK
authors.lastname: Kee
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Chang-Yun
authors.initials: CY
authors.lastname: Yoon
authors.affiliation: Ewha Institute of Convergence Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea.
authors.forename: Hyung Jung
authors.initials: HJ
authors.lastname: Oh
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Jung Tak
authors.initials: JT
authors.lastname: Park
authors.affiliation: Division of Nephrology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
authors.forename: Tae Ik
authors.initials: TI
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yoo
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Shin-Wook
authors.initials: SW
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea; Institute of Kidney Disease Research, Yonsei University, Seoul, Korea.
authors.forename: Seung Hyeok
authors.initials: SH
authors.lastname: Han
keywords: Acute kidney injury; Body mass index; Continuous renal replacement therapy; Mortality; Obesity