C reactive protein and long-term risk for chronic kidney disease: a historical prospective study

Introduction: C reactive protein (CRP) is an acute phase reactant that primarily produced by hepatocytes yet may be locally expressed in renal tubular cells. We assessed the association of CRP and the risk for chronic kidney disease (CKD) development. Methods: Historical prospective cohort study was conducted on subjects attending a screening center in Israel since the year 2000. Subjects with an estimated GFR (eGFR) above 60 ml/min/1.73 m² at baseline were included, and high sensitive (hs) CRP levels as well as eGFR were recorded for each visit. Follow up continued for at least 5 years for each subject until 2013. Risk for CKD at end of follow up was assessed in relation to mean hs-CRP levels of each subject. The confounding effects of other predictors of CKD were examined. A logistic regression model treating CRP as a continuous variable was further applied. Results: Out of 4,345 patients, 42 (1 %) developed CKD in a mean follow up of 7.6 ± 2 years. Elevated levels of CRP were associated with greater risk for CKD (crude OR 4.17, 95 % CI 1.46–11.89). The OR for the association of CRP with CKD when controlling for age and gender was 5.2 (95 % CI 1.7–16.2). When controlling for established renal risk factors, elevated CRP levels remained significantly associated with greater risk for CKD (OR 5.42, 95 % CI 1.76–16.68). When applying logistic regression models treating CRP as a continuous variable, for patients with diabetes mellitus (DM), hypertension (HTN) or eGFR between 60–90 ml\min\1.73 m², the predictive role of CRP for CKD was highly significant. Conclusion: Elevated CRP level is an independent risk factor for CKD development. In patients with DM, HTN or baseline eGFR between 60–90 ml\min\1.73 m² its predictive role is enhanced.