title: Body mass index and mortality in patients on maintenance hemodialysis: a meta-analysis.
abstract: OBJECTIVE
  In patients undergoing maintenance hemodialysis (MHD), increasing numbers of studies have reported a reduced mortality in patients with an increased body mass index (BMI). This article provides a meta-analysis on the assessment of the relationship between BMI and mortality in MHD patients.
  
  
  METHODS
  A systemic literature review was conducted to identify studies that examined all-cause mortality, with or without cardiovascular events, on the basis of bodyweight or obesity measures in MHD population published before October 2012.
  
  
  RESULTS
  Eight observational studies with a total of 190,163 patients were included. Compared to the individuals with a normal BMI, overweight patients and obese patients were associated with lower all-cause mortality [relative risk (RR) 0.86, 95% confidence interval (CI) 0.84-0.88; RR 0.77, 95% CI 0.75-0.78, respectively] and cardiovascular mortality (RR 0.86; 95% CI 0.81-0.91; RR 0.78, 95% CI 0.73-0.83, respectively). Underweight patients had relatively higher all-cause and cardiovascular mortality (RR 1.22, 95% CI 1.20-1.25; RR 1.19, 95% CI 1.11-1.28, respectively). In an obesity-stratified analysis, the patients with moderate or severe obesity presented a strongly decreased all-cause mortality risk (RR 0.64, 95% CI 0.61-0.68) and cardiovascular mortality risk (RR 0.63, 95% CI 0.53-0.75) compared to patients with mild obesity (RR 0.74, 95% CI 0.71-0.77; RR 0.81, 95% CI 0.75-0.87, respectively).
  
  
  CONCLUSIONS
  These findings show that overweight and obese patients have lower all-cause and cardiovascular mortality rates in patients undergoing MHD. Body weight management and optimized nutritional and metabolic support should help to reduce the high mortality rates that are prevalent in the hemodialysis population.
authors: Department of Nephrology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, No. 100 Haining Road, Shanghai, 200080, People's Republic of China.
authors: Ting
authors: T
authors: Li
authors: Jun
authors: J
authors: Liu
authors: Shuxian
authors: S
authors: An
authors: Yan
authors: Y
authors: Dai
authors: Qing
authors: Q
authors: Yu
mesh_terms: D015992:Body Mass Index; D006801:Humans; D006435:Renal Dialysis / Q000401:mortality*