PUBLISHED VERSION

Objectives: To study the body mass index (BMI) trajectory in patients with incident end-stage kidney disease and its association with all-cause mortality. Methods: This longitudinal cohort study included 17022 adult patients commencing hemodialysis [HD] (n510860) or peritoneal dialysis [PD] (n56162) between 2001 and 2008 and had $6-month follow-up and $2 weight measurements, using the Australia and New Zealand Dialysis and Transplant Registry data. The association of time-varying BMI with all-cause mortality was explored using multivariate Cox regression models. Results: The median follow-up was 2.3 years. There was a non-linear change in the mean BMI (kg/m) over time, with an initial decrease from 27.6 (95% confidence interval [CI]: 27.5, 27.7) to 26.7 (95% CI: 26.6, 26.9) at 3-month, followed by increments to 27.1 (95% CI: 27, 27.2) at 1-year and 27.2 (95% CI: 26.8, 27.1) at 3year, and a gradual decrease subsequently. The BMI trajectory was significantly lower in HD patients who died than those who survived, although this pattern was not observed in PD patients. Compared to the reference time-varying BMI category of 25.1–28 kg/m, the mortality risks of both HD and PD patients were greater in all categories of time-varying BMI ,25 kg/m. The mortality risks were significantly lower in all categories of time-varying BMI .28.1 kg/m among HD patients, but only in the category 28.1–31 kg/m among PD patients. OPEN ACCESS Citation: Badve SV, Paul SK, Klein K, Clayton PA, Hawley CM, et al. (2014) The Association between Body Mass Index and Mortality in Incident Dialysis Patients. PLoS ONE 9(12): e114897. doi:10.1371/ journal.pone.0114897 Editor: Rachel A. Nugent, University of Washington, United States of America Received: July 29, 2014 Accepted: November 15, 2014 Published: December 16, 2014 Copyright: 2014 Badve et al. This is an openaccess article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. The primary dataset for this manuscript was generated and made available to the authors by the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry, Adelaide, Australia. The ANZDATA Data Use Agreement between the ANZDATA Registry and the authors does not allow the authors to make the data publicly available. The authors confirm that all data underlying the findings can be obtained without restriction from the ANZDATA Registry. The interested researchers are advised to contact the ANZDATA Registry independently (email address requests@anzdata.org.au). Funding: The authors have no funding or support to report. Competing Interests: Drs. Badve, Klein and Clayton have reported that they have no potential conflicts of interest relevant to the contents of this paper to disclose. Dr. Paul has acted as a consultant and speaker for Novartis and Amylin Pharmaceuticals, LLC. He has received grants in support of investigator and investigator initiated clinical studies from Merck, Novo Nordisk and Pfizer, Amylin Pharmaceuticals and Hospira. Dr. Hawley has received consultancy fees from Amgen, Shire, Genzyme and Fresenius; research grant from Baxter and payment for lectures from Amgen and Shire. Dr. Brown has served as a member of the Fresenius ANZ Clinical Advisory Board and has received payment for lectures from Baxter ANZ PD Academy. Dr. Boudville has received research grant and payment for lectures from Roche; and travel grants from Roche, Amgen and Janssen Cilag. Dr. Polkinghorne has received PLOS ONE | DOI:10.1371/journal.pone.0114897 December 16, 2014 1 / 13 Conclusions: BMI changed over time in a non-linear fashion in incident dialysis patients. Time-varying measures of BMI were significantly associated with mortality risk in both HD and PD patients.