Association of peripheral eosinophil count with chronic kidney disease progression risk: a retrospective cohort study in Chinese population

The role of peripheral eosinophils in chronic kidney disease (CKD) requires further evaluation. We aimed to determine whether an eosinophil count increase is related to the occurrence of end-stage renal disease (ESRD).
This single-center, observational, retrospective cohort study was conducted between January 2016 and December 2018 in Hangzhou, China, and included 3163 patients, categorized into four groups according to peripheral eosinophil count (PEC) quartile values. The main outcome was ESRD development during follow-up. We evaluated the relationship between the serum eosinophil count, demographic and clinical information, and ESRD incidence. Cox proportional hazards models and Kaplan–Meier survival curves were used.
A total of 3163 patients with CKD were included in this cohort, of whom 1254 (39.6%) were females. The median (interquartile range [IQR]) age was 75 [64, 85] years, and the median (IQR) estimated glomerular filtration rate was 55.16 [45.19, 61.19] mL/min/1.73 m2. The median PEC was 0.1224 × 109/L (IQR, 0.0625–0.212). Among the 3163 patients with CKD, 273 (8.6%) developed ESRD during a median follow-up time of 443.8 [238.8, 764.9] days. Individuals in the highest PEC quartile had a 66.2% higher ESRD risk than those in the lowest quartile (hazard ratio, 1.662; 95% confidence interval, 1.165–2.372). The results from the Kaplan–Meier survival curves confirmed the conclusion.
Alongside traditional risk factors, patients with CKD and an elevated PEC are more likely to develop ESRD. Therefore, more attention should be paid to those patients with CKD who have a high PEC.

外周嗜酸性粒细胞（peripheral eosinophils）在慢性肾脏病（chronic kidney disease, CKD）中的作用仍有待进一步阐明。本研究旨在探讨嗜酸性粒细胞计数升高是否与终末期肾病（end-stage renal disease, ESRD）的发生存在关联。
本研究为单中心、观察性回顾性队列研究，于2016年1月至2018年12月在中国杭州开展，共纳入3163例患者，根据外周嗜酸性粒细胞计数（peripheral eosinophil count, PEC）的四分位数将其分为四组。本研究的主要结局为随访期间终末期肾病的发生情况。我们分析了外周血嗜酸性粒细胞计数、人口学特征与临床资料和终末期肾病发病率之间的关联，并采用Cox比例风险模型（Cox proportional hazards models）及Kaplan–Meier生存曲线（Kaplan–Meier survival curves）进行统计分析。
本队列共纳入3163例慢性肾脏病患者，其中女性1254例，占比39.6%。患者的年龄中位数（四分位数间距[IQR]）为75[64,85]岁，估算肾小球滤过率中位数（四分位数间距）为55.16[45.19,61.19] mL/min/1.73m²。外周嗜酸性粒细胞计数中位数为0.1224×10^9/L（四分位数间距：0.0625~0.212）。随访期间，共有273例（8.6%）患者进展为终末期肾病，随访时间中位数为443.8[238.8,764.9]天。外周嗜酸性粒细胞计数最高四分位组患者的终末期肾病发病风险较最低四分位组升高66.2%（风险比：1.662；95%置信区间：1.165~2.372）。Kaplan–Meier生存曲线分析结果验证了上述结论。
除传统危险因素外，外周嗜酸性粒细胞计数升高的慢性肾脏病患者更易进展为终末期肾病。因此，临床应更加关注外周嗜酸性粒细胞计数偏高的慢性肾脏病患者。