A Nomogram to Predict Contrast Induced Nephropathy in Patients Undergoing Percutaneous Coronary Intervention: Is the “Anti-Aging” Agent Klotho a Candidate Predictor?

Contrast-induced nephropathy (CIN) is the third leading cause of hospital-acquired acute kidney injury (AKI). Emerging evidence has revealed that soluble klotho (sklotho) could be a novel biomarker for early AKI diagnosis. The aims of this study were to assess the predictive role of sklotho for CIN and to develop a prediction nomogram in patients undergoing percutaneous coronary intervention (PCI). This study is registered on Clinicaltrials.gov (NCT 02650336).Patients aged 18 years or older undergoing planned PCI were prospectively recruited between May 2014 and July 2015. CIN was defined as an increase in serum creatinine of 0.5 mg/dL within 48-72 hours after the procedure. Plasma sklotho was measured by enzyme linked immunosorbent assay (ELISA). Stratified analysis, interaction test, covariate screening, and curve fitting were performed to explore the association between sklotho and CIN. A nomogram was then developed and validated using the bootstrapped technique.A total of 192 patients aged 54.75 ± 12.19 years were selected, 32 (16.7%) of whom were diagnosed with CIN. A logistic regression model indicated significant associations between CIN and sklotho, age > 75 years, diabetes, and the Mehran risk score. Saturation effects analysis detected a two-stage change between sklotho and CIN, with the inflection point was 477.4 pg/mL. The area under the ROC curve was 0.758 and the sensitivity and specificity of this point were 90.6% and 53.9%, respectively. A nomogram was developed for the prediction of CIN and showed a bootstrapped-corrected area under the curve value of 0.913. In addition, sklotho significantly increased the predictive value of the nomogram.A strong association between sklotho and CIN was identified in patients undergoing elective PCI. A lower level of sklotho would be well correlated with CIN. The nomogram with sklotho is a useful tool to predict CIN in patients who will undergo PCI.