Neutrophil Percentage as a Potential Biomarker of Acute Kidney Injury Risk and Short-Term Prognosis in Patients with Acute Myocardial Infarction in the Elderly

Abstract

Objective: This study aimed to explore the association of preoperative neutrophil percentage (NEUT%) with the risk of acute kidney injury (AKI) in patients with acute myocardial infarction (AMI) having undergone coronary interventional therapy.

Methods: A single-center, retrospective and observational study was conducted. From December 2012 to June 2021, patients with AMI were enrolled and divided into AKI group and non-AKI group. The NEUT% in the two groups was compared. The association between NEUT% with the risk of post-AMI AKI was analyzed by univariate and multivariable logistic regression. Kaplan-Meier survival curve was drawn to evaluate the prognostic ability of NEUT% for short-term all-cause death following AMI.

Results: A total of 3001 consecutive patients were enrolled with an average age of 64.38 years. AKI occurred in 327 (10.9%) patients. The NEUT% was higher in the AKI group than in the non-AKI group ([76.65±11.43]% versus [73.22±11.83]%, P<0.001). NEUT% was also identified as an independent risk factor for AKI in AMI patients after adjustment (OR=1.021, 95% CI: 1.010-1.033, P < 0.001). Compared with those at the lowest quartile of NEUT%, the patients at quartiles 2-4 had a higher risk of AKI (P for trend = 0.003). The odds of AKI increased by 29.0% as NEUT% increased by 1 standard deviation (OR=1.290, 95% CI: 1.087-1.531, P = 0.004). After a median of 35 days follow-up, 93 patients died. Patients with a higher NEUT% presented a higher risk of all-cause death after AMI (Log rank: χ² =24.753, P<0.001).

Conclusion: In AMI patients, the peripheral blood NEUT% was positively associated with the odds of AKI and short-term all-cause mortality. NEUT% may provide physicians with more information about disease development and prognosis.

Keywords: acute kidney injury; acute myocardial infarction; neutrophil percentage.

Figure 1

Study flow chart.

Figure 2

Neutrophil percentage levels in different groups and the relation of neutrophil percentage with the risk of AKI in a restricted cubic splines model. (A) The violin plot reflects the distribution and probability density of neutrophil percentage levels between the two groups, with dotted lines representing the 25th, 50th, and 75th percentiles. ***P <0.001. (B) The relation of neutrophil percentage with the risk of AKI on a continuous scale. X-axis represents neutrophil percentage. Y-axis represents the probability of AKI. Dashed lines indicate 95% CI. From left to right, the triangles indicate the 25th, 50th, and 75th percentile. (C) The relation between neutrophil percentage and the risk of AKI by restricted cubic splines. The odds ratio is indicated by the solid blue line, and the 95% CI is represented by the shaded regions derived from the three-node restricted cubic spline regression. The horizontal reference line represented by a dashed line indicates a odds ratio of 1.0, and the vertical reference line is the corresponding neutrophil percentage at this time.

Figure 3

Survival analyses according to neutrophil percentage quartiles and the incidence of AKI. (A) Short-term survival rate according to neutrophil percentage quartiles (Q1 versus Q2 and Q3 and Q4); (B) Survival rate between AKI group and non-AKI group.

Figure 4

Correlation of variables in AMI patients. The diagonals show the distribution; the lower left part shows a two-variable scatter diagram with fitting lines; the upper right shows the correlation coefficient and significance level, and the numbers represent the correlation coefficient. ***P < 0.001.