Serum C-reactive protein and leptin as predictors of kidney disease progression in the Modification of Diet in Renal Disease Study

Background. In vitro and in vivo data suggest that markers of inflammation and nutritional status may be risk factors for the progression of chronic kidney disease. Methods. We investigated whether higher levels of C-reactive protein (CRP) and leptin were risk factors for progression of chronic kidney disease in the Modification of Diet in Renal Disease (MDRD) Study. Frozen samples were assayed for high sensitivity C-reactive protein (CRP) or leptin in 804 patients. CRP and leptin were then evaluated as risk factors for glomerular filtration rate (GFR) decline using univariate and multivariable analyses. Results. At baseline, the mean (median) CRP in Study A (GFR between 25 and 55 mL/min/1.73 m(2)) and Study B (GFR between 13 and 24 mL/min/1.73 m(2)) were 0.48 (0.25) and 0.46 (0.20) mg/dL, respectively, while the mean (median) leptin in Study A and Study B were 15.2 (9.80) and 15.1 (7.80) ng/mL, respectively. Mean follow-up time was 2.2 years. The mean GFR decline was -4.33 and -3.65 mL/min/year in Study A and 13, respectively. There was no significant association between the rate of GFR decline with the level of CRP or leptin in multivariable analysis in Study A [0.08 (-0.14, 0.30) mL/min/year slower GFR decline per twofold increase in CRP level; and 0.14 (-0.13, 0.40) mL/min/year slower GFR decline per twofold increase in leptin level], or in multivariable analysis in Study B [-0.05 (-0.28, 0.18) mL/min/year faster GFR decline per twofold increase in CRP level; and -0.12 (-0.42, 0.19) mL/min/year faster GFR decline per twofold increase in leptin level]. Conclusions. Higher serum levels of CRP and leptin are not independent risk factors for progression of non-diabetic kidney disease.