空气污染暴露与危重患者死亡风险的关联以及血细胞比值在关联中的中介效应

Associations between air pollution exposure and mortality risk of critically ill patients and mediation effects of blood cell count ratio in associations

目的研究主要空气污染物(PM_(2.5)、PM_(10)、NO_(2)、SO_(2)、O_(3)和CO)暴露与ICU住院患者28 d全因死亡之间的关联。方法收集2018年8月至2019年8月和2021年5月至2022年5月湖北省人民医院和荆州中心医院重症监护室收治危重患者的电子病历数据。根据患者居住地和入院日期前2个月平均浓度评估患者暴露于空气污染物的水平。使用广义线性回归模型估计单个空气污染物暴露与入住ICU的危重患者28 d全因死亡风险之间的关联;然后以单个空气污染物暴露为亚组,检验患者的疾病特征(年龄、性别、吸烟、饮酒、住院天数和SOFA评分)对患者28 d死亡这一主要结局指标的效应量和可信区间;并构建中介模型研究血细胞计数比值是否是潜在的中介变量。结果最终3772例入住ICU的危重患者纳入研究,28 d非意外全因病死率为40.0%(1509/3772)。研究证实PM_(2.5)、NO_(2)和CO与ICU患者28 d全因死亡风险呈显著正相关,而O_(3)与死亡风险呈负相关。男性是NO_(2)和CO暴露与ICU患者全因死亡的危险因素,SOFA评分>3分是NO_(2)暴露与ICU患者全因死亡的危险因素。中性粒细胞/淋巴细胞比值(NLR)在PM_(2.5)、CO暴露与ICU患者死亡风险的关联中发挥中介效应。结论空气污染物(PM_(2.5)、NO_(2)、CO)暴露与ICU患者28 d全因死亡风险之间具有显著正向关联。即使低水平的空气污染仍然与危重患者这一脆弱群体的死亡风险有正向关联。

Objective To investigate the association between exposure to major air pollutants(including PM_(2.5),PM_(10),NO_(2),SO_(2),O_(3)and CO)and 28-day all-cause mortality in patients admitted to the intensive care unit(ICU).Methods The electronic medical records of critically ill patients admitted to the ICU in Hubei Province General Hospital and Jingzhou Central Hospital were collected from August 2018 to August 2019 and from May 2021 to May 2022.Patients'exposure to air pollutants was assessed based on the average concentrations at their place of residence during the previous two months.A generalized linear regression model was used to estimate the association between air pollutant exposure and 28-day all-cause mortality in critically ill patients.Subgroup analysis was then conducted to examine the impact of individual air pollutant exposure on 28-day mortality,which served as the primary outcome in this study.The effect size and confidence interval were adjusted for patient characteristics including age,gender,smoking or drinking habits,length of hospital stay,and SOFA score.Additionally,mediation analysis was conducted using the mediation package(Bruce R)in R software.The direct effect represented the association between exposure to air pollutants and risk of mortality,while the indirect effect aimed to assess whether neutrophil-lymphocyte ratio(NLR),platelet-lymphocyte ratio(PLR),and monocyte-lymphocyte ratio(MLR)served as mediating variables in the correlation between exposure to air pollutants and mortality risk.Results The study included a total of 3772 critically ill patients admitted to the ICU,with a 28-day all-cause mortality rate of 40.0%(1509/3772).A signifi cant positive correlation was observed between an incremental increase of 1μg/m^(3)in air pollutants(specifi cally PM_(2.5),NO_(2)and CO)and an elevated risk of mortality within 28 days among critically ill patients.Conversely,there is an inverse relationship between O_(3)levels and mortality risk.Additionally,male gender and SOFA rating>3 scores were identifi ed as independent risk factors for all-cause mortality in ICU patients exposed to NO_(2)or CO.The Neutrophil/lymphocyte ratio(NLR)played a mediating role in the correlation between PM_(2.5)or CO exposure and mortality risk,accounting for 9.09%or 4.71%of the correlations,respectively.Conclusions The exposure to air pollutants(PM_(2.5),NO_(2),CO)signifi cantly associate with a high risk of 28-day all-cause mortality in ICU patients.Even at low levels of air pollution,NO_(2),CO remains positively correlate with the mortality risk in critically ill patients,who belong to a vulnerable population.