Association of Neutrophil-to-lymphocyte Ratio with Contrast-induced Nephropathy in Patients with Non-ST-elevation Acute Coronary Syndrome Treated with Percutaneous Coronary Intervention

Background A higher neutrophil-to-lymphocyte ratio (NLR) is associated with poor clinical outcomes in various cardiovascular diseases, including acute coronary syndromes. However, the relationship between NLR and contrast-induced nephropathy (CIN) in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI) has not been known. Hence, we investigated whether admission NLR is associated with CIN after PCI in patients with NSTE-ACS. Methods A total of 478 patients (mean age 62.8 +/- 12.6 years, and 64.2% men), who were admitted to our hospital for NSTEACS and underwent PCI with stent, were recruited. Neutrophil-to-lymphocyte ratio was calculated via dividing neutrophil count by lymphocyte count. The patients were divided into two groups: CIN (+) and CIN (-). Contrast-induced nephropathy was defined as a >= 0.5 mg/dL and/or a >= 25% increase in serum creatinine within 48-72 hours post-PCI. Results Admission NLR was significantly higher in patients with CIN than in patients without CIN (median 5.43, interquartile range 3.23-7.73 vs. median 2.59, interquartile range 1.83-3.88, P<0.001). On multivariate analysis, NLR >= 3.46 value (OR=2.631, 95% CI 1.146-6.060, P=0.022), estimated glomerular filtration rate (OR=0.963, P=0.004), high sensitivity C-reactive protein (OR=1.028, P=0.016) were independent factors of CIN. Conclusion Increased NLR is independently associated with risk of CIN in NSTE-ACS patients treated by PCI.