血电解质与重症新型冠状病毒肺炎患者预后的关系

Relationship between blood electrolytes and prognosis of patients with severe coronavirus disease 2019

目的分析重症新型冠状病毒肺炎(新冠肺炎)患者血电解质与预后的关系,为临床决策提供帮助。方法收集2020年1月21日至3月4日上海援鄂医疗队在武汉市第三医院重症监护病房(ICU)收治的重症新冠肺炎确诊患者的临床资料,排除不符合条件的患者,最终纳入110例患者。分析患者的性别、年龄、入院时体温、心率、收缩压和舒张压、临床症状、症状出现时间、发热持续时间、入ICU时相关指标(包括血钾、血氯、血钠、血钙、血磷和血镁等)及预后情况。分别按血钾和血钙水平以及血钾/血钙比值将患者分组,采用Kaplan-Meier生存曲线分析各组患者的生存情况,使用限制性立方样条图分析血钾/血钙比值与患者预后的关系,使用Cox回归模型分析不同模型中各指标与患者预后的关系。结果110例重症新冠肺炎患者中存活78例,死亡32例。与存活组相比,死亡组患者血钾更高〔mmol/L:4.25(3.80,4.65)比3.90(3.60,4.20),P<0.05〕,血钙更低(mmol/L:2.00±0.14比2.19±0.18,P<0.05)。Kaplan-Meier生存曲线显示,血钾>4.2 mmol/L组患者预后比<3.8 mmol/L组和3.8~4.2 mmol/L组差(P=0.011);血钙>2.23 mmol/L组患者预后比<2.03 mmol/L组和2.03~2.23 mmol/L组好,且血钙越低组患者预后越差(P=0.00015)。Cox回归分析显示,模型1(单一血钾或血钙)的血钾和血钙风险比(HR)分别为2.08和0.01,模型2(模型1+年龄+性别)校正后血钾和血钙HR分别为1.98和0.01,均与患者预后明显相关(均P<0.05)。与血钾/血钙比值<1.7组和1.7~1.9组相比,>1.9组患者的血钾水平和机械通气比例更高,血钙水平和存活比例更低,入院至入ICU时间更长。Kaplan-Meier生存曲线显示,血钾/血钙比值>1.9组患者的累积生存率最低(P<0.0001),而<1.7组和1.7~1.9组累积生存率比较差异无统计学意义。校正年龄和性别后的限制性立方样条图显示,血钾/血钙比值>1.8组患者的HR均>1。Cox回归分析纳入其他指标校正后显示,血钾/血钙比值仍与患者预后相关(HR=4.85,P=0.033)。结论入ICU时的血钾和血钙水平及血钾/血钙比值与重症新冠肺炎患者预后相关;血钾/血钙比值为患者死亡的独立危险因素,比值越高患者预后越差。

Objective To analyze the relationship between blood electrolytes and the prognosis of patients with severe coronavirus disease 2019(COVID-19)and to provide assistance for clinical decision-making.Methods The clinical data of patients with severe COVID-19 admitted to intensive care unit(ICU)of the Wuhan Third Hospital by the Shanghai aid-Hubei medical team from January 21 to March 4,2020 were collected.Excluding ineligible patients,110 patients were finally enrolled.The patients'gender,age,temperature,heart rate,systolic and diastolic blood pressure,clinical symptoms at admission,time of symptom onset,duration of fever,and relevant indicators at admission to ICU(including blood potassium,chloride,sodium,calcium,phosphorus,and magnesium,etc.)and prognosis were analyzed.The patients were grouped by blood potassium or calcium levels or blood potassium/calcium ratio.The Kaplan-Meier survival curves were used to analyze the survival of patients in each group.The relationship between the potassium/calcium ratio and the prognosis was analyzed using restricted cubic spline plots.The relationship between each index in the different models and the prognosis was analyzed using Cox regression models.Results Among 110 severe COVID-19 patients,78 cases survived,and 32 cases died.Compared with the surviving group,patients in the death group had higher blood potassium levels[mmol/L:4.25(3.80,4.65)vs.3.90(3.60,4.20),P<0.05]and lower blood calcium levels(mmol/L:2.00±0.14 vs.2.19±0.18,P<0.05).The Kaplan-Meier survival curves showed that patients in the potassium>4.2 mmol/L group had a worse prognosis than the potassium<3.8 mmol/L group and the potassium 3.8-4.2 mmol/L group(P=0.011),patients in the calcium>2.23 mmol/L group had a better prognosis than the calcium<2.03 mmol/L group and the calcium 2.03-2.23 mmol/L group,and the lower calcium group had a worse prognosis(P=0.00015).Cox regression analysis showed that the hazard ratio(HR)of blood potassium and calcium were 2.08 and 0.01,respectively,in model 1(single blood potassium or calcium)and in model 2(model 1 plus age and gender),the HR of blood potassium and calcium were 1.98 and 0.01 respectively,which were significantly associated with patient prognosis(all P<0.05).Patients in the group with the potassium/calcium ratio>1.9 had higher blood potassium levels and a higher proportion of mechanical ventilation,lower calcium levels and lower proportion of survival,and longer time of ICU admission compared with the groups with the potassium/calcium ratio<1.7 and 1.7-1.9.The Kaplan-Meier survival curves showed that the survival rate of the potassium/calcium ratio>1.9 group was the lowest(P<0.0001),and there was no statistically significant difference in survival between the potassium/calcium ratio<1.7 group and the potassium/calcium ratio 1.7-1.9 group.A restricted cubic spline plot corrected for age and gender showed that patients in the potassium/calcium ratio>1.8 group had HR values>1.Cox regression analysis corrected for other indicators showed that the potassium/calcium ratio was still associated with patient prognosis(HR=4.85,P=0.033).Conclusions Blood potassium,calcium,and the potassium/calcium ratio at ICU admission are related to the prognosis of patients with severe COVID-19,and the potassium/calcium ratio is an independent risk factor for the death of patients.The higher the potassium/calcium ratio,the worse the prognosis of patients.