title: Body composition and survival in dialysis patients: results from an international cohort study.
abstract: OBJECTIVE
  High body mass index appears protective in hemodialysis patients, but uncertainty prevails regarding which components of body composition, fat or lean body mass, are primarily associated with survival.
  
  
  METHODS
  Data between April 2006 and December 2012 were extracted from the Fresenius Medical Care Europe subset of the international MONitoring Dialysis Outcomes initiative. Fresenius Medical Care Europe archives a unique repository of predialysis body composition measurements determined by multifrequency bioimpedance (BCM Body Composition Monitor). The BCM Body Composition Monitor reports lean tissue indices (LTIs) and fat tissue indices (FTIs), which are the respective tissue masses normalized to height squared, relative to an age- and sex-matched healthy population. The relationship between LTI and FTI and all-cause mortality was studied by Kaplan-Meier analysis, multivariate Cox regression, and smoothing spline ANOVA logistic regression.
  
  
  RESULTS
  In 37,345 hemodialysis patients, median (25th-75th percentile) LTI and FTI were 12.2 (10.3-14.5) and 9.8 (6.6-12.4) kg/m(2), respectively. Median (25th-75th percentile) follow-up time was 266 (132-379) days; 3458 (9.2%) patients died during follow-up. Mortality was lowest with both LTI and FTI in the 10th-90th percentile (reference group) and significantly higher at the lower LTI and FTI extreme (hazard ratio [HR], 3.37; 95% confidence interval [95% CI], 2.94 to 3.87; P<0.001). Survival was best with LTI between 15 and 20 kg/m(2) and FTI between 4 and 15 kg/m(2) (probability of death during follow-up: <5%). When taking the relation between both compartments into account, the interaction was significant (P=0.01). Higher FTI appeared protective in patients with low LTI (HR, 3.37; 95% CI, 2.94 to 3.87; P<0.001 at low LTI-low FTI, decreasing to HR, 1.79; 95% CI, 1.47 to 2.17; P<0.001 at low LTI-high FTI).
  
  
  CONCLUSIONS
  This large international study indicates best survival in patients with both LTI and FTI in the 10th-90th percentiles of a healthy population. In analyses of body composition, both lean tissue and fat tissue compartments and also their relationship should be considered.
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany; Daniele.Marcelli@fmc-ag.de.
authors.forename: Daniele
authors.initials: D
authors.lastname: Marcelli
authors.affiliation: Fresenius Medical Care, Waltham, Massachusetts;
authors.forename: Len A
authors.initials: LA
authors.lastname: Usvyat
authors.affiliation: Renal Research Institute, New York, New York; Mount Sinai Hospital, New York, New York;
authors.forename: Peter
authors.initials: P
authors.lastname: Kotanko
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany;
authors.forename: Inga
authors.initials: I
authors.lastname: Bayh
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany; University of Montpellier I, Montpellier, France;
authors.forename: Bernard
authors.initials: B
authors.lastname: Canaud
authors.affiliation: Fresenius Medical Care Asia-Pacific, Hong Kong;
authors.forename: Michael
authors.initials: M
authors.lastname: Etter
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany; Danube University, Krems, Austria;
authors.forename: Emanuele
authors.initials: E
authors.lastname: Gatti
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany;
authors.forename: Aileen
authors.initials: A
authors.lastname: Grassmann
authors.affiliation: University of California-Santa Barbara, Santa Barbara, California;
authors.forename: Yuedong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Fresenius Medical Care, Buenos Aires, Argentina; and.
authors.forename: Cristina
authors.initials: C
authors.lastname: Marelli
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany;
authors.forename: Laura
authors.initials: L
authors.lastname: Scatizzi
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany;
authors.forename: Andrea
authors.initials: A
authors.lastname: Stopper
authors.affiliation: Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Frank M
authors.initials: FM
authors.lastname: van der Sande
authors.affiliation: Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Kooman
mesh_terms: D050154:Adiposity; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D015992:Body Mass Index; D016022:Case-Control Studies; D016208:Databases, Factual; D017097:Electric Impedance; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007674:Kidney Diseases / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000009:adverse effects / Q000401:mortality; D018570:Risk Assessment; D012307:Risk Factors; D013057:Spectrum Analysis; D013997:Time Factors; D016896:Treatment Outcome
keywords: bioimpedance; dialysis; fat tissue; lean tissue; survival