Serum interleukin-6 concentration predicts contrast-induced nephropathy in patients undergoing percutaneous coronary...

Contrast media are being widely applied for both diagnostic and therapeutic purposes. This has resulted in increasing incidence of contrast-induced nephropathy (CIN).

We aimed to investigate the value of baseline serum IL-6 concentrations in predicting CIN before the rise of serum creatinine (SCr) in patients undergoing percutaneous coronary intervention. Seventy four Caucasian patients were enrolled. CIN was defined as an increase in SCr concentration of more than 44 micromol/L, or a 25% increase above baseline within 48 hours after contrast administration.

CIN developed in 16 out of 74 patients (21.6%). The median concentration of IL-6 was 3.2 pg/mL. The median IL-6 concentration on admission was lower in patients who subsequently did not develop CIN (2.7 pg/mL versus 8.3 pg/mL, p < 0.0001). Receiver operating characteristics analysis showed a high diagnostic value of baseline SCr and IL-6. The cut-off value to predict CIN for IL-6 was over 4.0 pg/mL (sensitivity 88%, specificity 76%, PPV 50%, NPV 96%). Multivariate logistic regression analysis revealed three independent predictors of CIN: IL-6 (OR 1.43; 95%CI: 1.17-1.76), serum creatinine (OR 1.79; 95%CI: 1.1-3.39), and ejection fraction (OR 0.86; 95%CI: 0.50-0.95).

Increased concentrations of IL-6 on admission are associated with subsequent CIN. Our study proposes that IL-6 be added to the list of potential markers that could be used, along with renal function parameters, in clinical practice.