Effects of extreme high and low temperatures on admission risk of acute ischemic stroke and its etiology subtypes: a time series analysis in Wuhan, China / 国际脑血管病杂志

ABSTRACT

Objective@#To investigate the effects of extreme high and low temperatures on admission risk of acute ischemic stroke (AIS) and its etiology subtypes.@*Methods@#From January 1, 2016 to December 31, 2017, the data of inpatients with AIS from Zhongnan Hospital of Wuhan University and the meteorological data and air pollution data from China Meteorological Data Network in the same period were collected continuously. According to TOAST etiology criteria, the patients were divided into large artery atherosclerosis (LAA), small vessel occlusion (SVO), cardioembolism (CE), and stroke of other etiology (SOE). A time series analysis of the distributed lag model was used to investigate the effects of extreme high and low temperatures on the admission of patients with AIS and its etiology subtype, and air pollution, air pressure, humidity, and wind speed were used as confounding factors to exclude interference.@*Results@#A total of 1 413 patients with AIS were enrolled, including 906 men (64.4%), age 67.7±12.8 years. The thresholds of extreme low temperature (1%, 5% and 10% of the average temperature) were 0.7 ℃, 3.3 ℃, and 4.9 ℃. The thresholds of extreme high temperature (90%, 95% and 99% of the average temperature) were 29.2 ℃, 31.6 ℃, and 32.9 ℃. Extreme high temperature increased the risk of hospitalization in patients with AIS (lag 0 day; relative risk [RR] 1.54, 95% confidence interval [CI] 1.01-2.34). It was mainly related to the increased risk of hospitalization in patients with CE subtype (lag 0 day; RR 7.64, 95% CI 1.19-49.09). There was no significant correlation between the extreme low temperature and the risk of hospitalization of AIS (lag 2 days; RR 0.99, 95% CI 0.71-1.37), but it significantly increased the risk of hospitalization in patients with LAA subtypes (lag 2 days; RR 3.04, 95% CI 1.33-6.95), and it was still statistically significant at lag 3 days (RR 2.87, 95% CI 1.57-5.25) and lag 4 days (RR 2.19, 95% CI 1.15-4.15).@*Conclusion@#Extreme high temperature may increase the risk of hospitalization in patients with AIS and CE subtypes, while extreme low temperature may increase the risk of hospitalization in patients with LAA subtypes.