title: Association between body mass index and body fat in chronic kidney disease stages 3 to 5, hemodialysis, and peritoneal dialysis patients.
abstract: OBJECTIVE
  Chronic kidney disease (CKD) patients may present with altered body composition. Body mass index (BMI) is a simple method for evaluating body fat mass (FM) in the general population. In CKD patients, there are few reports demonstrating the association between BMI and body composition. Our objective was to investigate the reliability of BMI as an indicator of FM in patients with CKD stages 3 to 5.
  
  
  METHODS
  Seventy-eight nondiabetic CKD patients (aged 48, SD +/- 12 years; 45% male) and 30 healthy control subjects (aged 46, SD +/- 12 years; 40% male), matched for age and sex, were evaluated. Chronic kidney disease patients were divided, according to K/DOQI guidelines, into 27 subjects at stages 3 to 4 (mean glomerular filtration rate of 43 +/- 12 mL/minute; age, 52 +/- 10 years), and 51 at stage 5: 25 in hemodialysis (HD) (aged 45, SD +/- 12 years; 44% male), and 26 in peritoneal dialysis (PD) (aged 49, SD +/- 13 years; 42% male). Body mass index was calculated as weight/height(2), and body composition was evaluated through dual-energy x-ray absorptiometry.
  
  
  RESULTS
  There was no difference in median BMI (kg/m(2)) among healthy control subjects (24.8; range, 19.2-34.1), CKD stages 3 to 4 (26.4; range, 20.4-37.6), HD patients (24.5; range, 19.4-35.7), and PD patients (24.5; range, 20.2-37.7; P > .05). Likewise, no significant difference was verified in median body FM (kg) among control subjects (18.8; range, 9.2-36.5), CKD stages 3 to 4 (21.2; range, 11.6-37.9), HD patients (17.1; range, 4.8-38.9), and PD patients (20.1; range, 6.5-41.5; P > .05). Moreover, a positive and significant correlation was found between BMI and FM (kg) in CKD stages 3 to 4 (Rho = 0.67, P = .0002), in HD patients (Rho = 0.67, P = .0002), in PD patients (Rho = 0.79, P < .0001), and in control subjects (Rho = 0.79, P < .0001). Although BMI and lean body mass (in kg) was significantly correlated in CKD stages 3 to 4 (Rho = 0.58, P = .001) and healthy control subjects (Rho = 0.30, P = .007), no significant correlation was found in HD patients (Rho = 0.19, P = .34) and in PD patients (Rho = 0.17, P = .38).
  
  
  CONCLUSIONS
  Body composition did not differ in patients with CKD stages 3 to 5, and between dialysis modalities. Although BMI was strongly and significantly correlated with body FM in CKD patients at stages 3 to 5, lean body mass was not. These findings suggest that BMI is a reliable indicator of body FM in this CKD population.
authors: Center for Health and Biological Sciences, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil. cyntia.leinig@pucpr.br
authors: Cyntia
authors: C
authors: Leinig
authors: Roberto
authors: R
authors: Pecoits-Filho
authors: Marcelo Mazza
authors: MM
authors: Nascimento
authors: Simone
authors: S
authors: Gonçalves
authors: Miguel Carlos
authors: MC
authors: Riella
authors: Cristina
authors: C
authors: Martins
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects / Q000379:methods*; D006435:Renal Dialysis / Q000009:adverse effects / Q000379:methods*; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers