Resting energy expenditure of chronic kidney disease patients: influence of renal function and subclinical inflammation.
BACKGROUND
The resting energy expenditure (REE) of patients with chronic kidney disease (CKD) might be influenced by the degree of renal function and by a subclinical inflammatory condition. The aim of this study is to evaluate the impact of these 2 variables on the REE of patients with CKD.


METHODS
A cross-sectional study was performed on 91 nondialyzed and nondiabetic patients with CKD with no clinical signs of inflammation. Patients were divided into quartiles of creatinine clearance (CrCl) and tertiles of C-reactive protein (CRP) level. REE was measured by means of indirect calorimetry, and the presence of a subclinical inflammatory condition was assessed by means of serum CRP concentration.


RESULTS
CrCl interquartile ranges calculated were: quartile 1 (CrCl < or = 18 mL/min [< or =0.30 mL/s]; n = 24); quartile 2 (CrCl, 19 to 29 mL/min [0.31 to 0.48 mL/s]; n = 22); quartile 3 (CrCl, 30 to 42 mL/min [0.49 to 0.70 mL/s]; n = 23), and quartile 4 (CrCl > or = 43 mL/min [> or =0.71 mL/s]; n = 22). Nonadjusted REE and REE adjusted for sex, age, and lean body mass did not differ among the 4 CrCl quartiles. The following ranges were calculated for CRP tertiles: tertile 1 (CRP < or = 0.14 mg/dL; n = 30), tertile 2 (CRP, 0.15 to 0.49 mg/dL; n = 31), and tertile 3 (CRP > or = 0.50 mg/dL; n = 30). The nonadjusted REE in CRP tertile 3 was significantly greater than those in tertiles 1 and 2. REE adjusted for sex, age, and lean body mass was greater in CRP tertile 3 than tertile 1, a difference equivalent to 123.7 kcal/d (P = 0.003; 95% confidence interval, 42.9 to 204.5). A borderline difference was observed between CRP tertiles 3 and 2. When analyzing the entire group, REE did not correlate with either serum creatinine level or CrCl, and a borderline correlation between REE and log of CRP was observed (r = 0.19; P = 0.07).


CONCLUSIONS
This study suggests that REE is not influenced by degree of renal function, but it may be elevated during a condition of subclinical inflammation.
Avesani
Carla Maria
CM
Division of Nephrology, Dialysis Unit of the Federal University of São Paulo, São Paulo, Brazil.
Draibe
Sergio Antonio
SA
Kamimura
Maria Ayako
MA
Colugnati
Fernando Antonio Basile
FA
Cuppari
Lilian
L
D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000503:physiopathology; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology*