Impact of neutrophil-to-lymphocyte ratio on clinical outcomes in patients with or without chronic kidney disease undergoing percutaneous coronary intervention
Authors: Oliva A , Vogel B , Sartori S , Cao D , Bay B , Smith K , Gitto M , Dangas G , Pocock S , Bhatt D , Ridker P , Kini A , Sharma S , Mehran R 
Published: October 2024

Abstract

Background
Neutrophil-to-lymphocyte ratio (NLR) has recently emerged as inexpensive inflammatory biomarker associated with worse cardiovascular outcomes. However, little is known about its role in risk stratification of patients with both chronic kidney disease (CKD) and coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI).

Purpose
We aimed to evaluate the clinical impact of baseline NLR in patients with and without CKD undergoing PCI.

Methods
We retrospectively evaluated all consecutive patients undergoing PCI between 2012-2022 in a large tertiary US center. We excluded patients without available NLR and those who were deemed to have active hematological or infective diseases, including patients with extremely low or high lymphocyte and neutrophil counts or with hs-CRP above 10 mg/L. Quartiles of NLR were derived in the overall population and patients were stratified according to presence of CKD (eGFR &lt; 60 ml/min). Within each group, we estimated the risk of adverse events using the lowest NLR quartile as reference. The primary endpoint was 12-month incidence of major adverse cardiovascular events (MACE), defined as the composite of all-cause death, myocardial infarction, or stroke. Secondary endpoints included incidence of clinically relevant bleeding and contrast-associated acute kidney injury (CA-AKI), defined as ≥ 0.3 mg/dL or ≥ 50% serum creatinine increase from baseline.

Results
A total of 7,287 patients were included in the analysis; of these 2,008 (27.6%) had CKD and 5,279 (72.4%) did not. CKD patients (mean eGFR 40.8±16.1 ml/min) were older, had more comorbidities, and presented with higher hs-CRP levels and a greater estimated risk of CA-AKI. Overall, patients with elevated NLR had more severe CAD and underwent more complex PCI. In CKD patients, incidence of adverse events increased stepwise and those in the 4th NLR quartile had the highest adjusted risks of MACE (HRadj 1.86, 95% CI 1.12-3.08; P=0.012), all cause death (HRadj 2.44, 95% CI 1.18-5.05; P=0.003) and bleeding (HRadj 1.74, 95% CI 1.07-2.84; P=0.002) at 1 year, as compared to those in the lowest quartile (Table 1). In patients without CKD, MACE and all-cause death incidences were numerically higher in the 4th quartile but risk estimates were no longer statistically significant after adjustment. The overall incidence of CA-AKI was much greater in the CKD group. When compared to the lowest quartile, patients in the 4th NLR quartile showed a trend for higher risk of CA-AKI in CKD group, while they had a significant increased risk in non-CKD group (Figure 1).

Conclusions
Elevated NLR is strongly associated with higher risk of MACE and all-cause mortality in CKD patients. Conversely, the risk of bleeding and CA-AKI is increased with elevated NLR in both CKD and non-CKD patients. Thus, NLR may further inform risk stratification of CKD patients undergoing PCI.