The role of inflammation in contrast-induced nephropathy

OBJECTIVE Global incidence of contrast-induced nephropathy (CIN) is 2-5%, but a recent Kenyan study highlighted a local incidence of 12-14% without offering an explanation for the higher incidence. This study proposes that inflammatory states confer a higher relative risk for development of CIN. Our objective was to determine the risk of developing CIN given the presence of an inflammatory state in patients in Kenya. METHODS Prospective cohort study of patients undergoing a contrast-enhanced CT (CECT) scan in a private university teaching hospital in Kenya and having no known risk factors for CIN. 423 patients were recruited and grouped into those without inflammation (unexposed) having serum C-reactive protein (CRP) levels ≤5 mg dl(-1) and those with evidence of inflammation having CRP levels >5 mg dl(-1). Serum creatinine (SCr) was measured before the CECT and 48 h following the CECT with CIN diagnosed by an increase of >25% in the SCr from the baseline. Relative risk was determined and multiple logistic regression analysis performed on biophysical variables and contrast volume to assess their effect on development of CIN. RESULTS Patients with high CRP levels had a relative risk of developing CIN of 2.16 compared with those with normal levels of CRP (p = 0.016). No statistically significant association was seen between biophysical variables or volume of contrast and development of CIN. CONCLUSION Ongoing inflammation doubles the likelihood of development of CIN. ADVANCES IN KNOWLEDGE This study highlights the importance of inflammation as a risk factor in the development of CIN.