Cystatin C is an early marker of contrast-induced nephropathy in patients with sepsis in the intensive care unit.

Contrast-induced nephropathy (CIN) is becoming an increasingly common cause of acute kidney injury in hospitalized patients. To evaluate the prevalence of CIN in critically ill patients, we conducted a prospective study on intensive care unit patients who had undergone diagnostic computed tomography scan or non-coronary angiography with intravenous administration of iodinated contrast media. Patient demographics, disease characteristics and biochemical markers, including cystatin C, creatinine and urea, were compared between the patients who developed and those who did not develop CIN. A total of 42 patients were diagnosed with sepsis, 52 were diagnosed with diabetes mellitus, 18 with ischemic heart disease and 49 with hypertension. We found a similar incidence of CIN among the groups (28.6-36.8%). There was no association of patient age, gender or body mass index with the development of CIN. In sepsis patients, cystatin C levels were significantly raised at baseline in patients who developed CIN (P = 0.020) and also on the day before CIN was detected (P = 0.035) and the day of CIN detection (P = 0.012). No associations with cystatin C or other serum or urinary biomarkers were detected in any of the other disease groups. In conclusion, a relatively high prevalence of CIN was found in all disease groups. No demographic or disease factors were found to be associated with the development of CIN. Cystatin C may be a useful early marker of CIN in sepsis patients, but further work is required to understand the difference in cystatin C expression levels in patients with different underlying pathologies.