Background: C-Reactive protein (CRP) level is elevated in kidney failure and may be related to malnutrition and cardiovascular disease (CVD). Data are limited regarding relationships between CRP levels and glomerular filtration rate (GFR), nutritional indices, and CVD in patients with earlier stages of kidney disease.
Methods: CRP was assayed from samples from the Modification of Diet in Renal Disease (MDRD) Study (n = 801). CRP distributions were compared between the MDRD Study and National Health and Nutrition Examination Survey (NHANES; 1999 to 2000). Associations between CRP level and GFR, nutritional indices, serum albumin levels, and CVD risk factors were examined in the MDRD Study.
Results: Geometric means of CRP, adjusted for age and sex, were similar in NHANES (0.23 mg/dL) and the MDRD Study (0.22 mg/dL). In the MDRD Study, CRP level was related directly to measures of body fat and CVD risk factors, inversely with serum albumin level and energy intake, and unrelated to GFR. In multivariable analysis adjusting for other determinants of serum albumin level, high CRP level (>0.6 mg/dL) was associated with a 0.07-g/dL (0.7-g/L; 95% confidence interval [CI], 0.03 to 0.12) lower mean serum albumin level. After adjusting for traditional CVD risk factors, the odds of CVD were 1.73 (95% CI, 1.07 to 2.78) times greater in subjects with a high CRP level.
Conclusion: GFR level does not appear to influence CRP level in the earlier stages of chronic kidney disease. CRP levels are independently associated with serum albumin level and CVD prevalence. Inflammation may be involved in the pathophysiological state of malnutrition and CVD in the earlier stages of predominantly nondiabetic kidney disease.