Effects Of Time Distribution And Temperature Change On The Occurrence Of Acute Type B Aortic Dissection

Objective:To explore the influence of time distribution and temperature change on the occurrence of acute type B aortic dissection,and to provide ideas for disease prevention and control and allocation of medical resources.Methods:In this study,the time distribution mainly counted the season,month,day and night changes of acute type B aortic dissection,which were reflected by the lowest temperature and difference in temperature.A total of 491 patients with acute type B aortic dissection from January 1,2015 to December 31,2019 in Subei people’s Hospital of Jiangsu Province were retrospectively analyzed.The inclusion criteria of this study were as follows:（1）first onset of aortic dissection.（2）patients with acute onset of aortic dissection,and the time of visit was less than 14 days after the onset of aortic dissection.Exclusion criteria:（1）subacute and chronic aortic dissection;（2）traumatic or iatrogenic aortic dissection;（3）non-first-time dissection;（4）not in Yangzhou urban area during the onset period;（5）the time of onset can not be accurately obtained from the case.A total of 428 patients were enrolled in the group.The clinical data of the patients such as age,sex,BMI,hospitalized date,minimum temperature and temperature difference on the day of admission were collected.According to the time provided by the consultation,the onset time was calculated,and the earliest onset date and exact time of each patient were calculated.The time was accurate to hours.The patients were divided into two groups:group A（patients greater than or equal to the age of 60）and group B（patients less than 60years old）.The observation index is（1）the influence of air temperature,season,month,diurnal change on the whole patient;（2）the effects of time factors and temperature factors on the incidence of patients of different ages.The statistical software was R version 4.0.2 and EXCEL 2012.The effects of time distribution and temperature changes on acute type B aortic dissection in the young and middle-aged and the elderly were observed and analyzed by circular analysis and generalized additive model.Results:A total of 428 patients were statistically analyzed,including the oldest age 95years old and the youngest age 29 years old.There were 229 patients in group A（69.78±7.45 years old）,including 180 males（78.6%）;B group（48.5±7.21 years old）and 168 males（82.9%）.The study found that the incidence of type B aortic dissection was obviously seasonal,with more cases in winter（32.8%）and less in summer（93cases,18.9%）.The total number of cases in January was the highest,with a total of 60cases（12.2%）,and the lowest in June,with a total of 18 cases（3.6%）.The seasonal,monthly and circadian rhythms of acute type B aortic dissection were analyzed by circular distribution Rayleigh test.It was found that January was the peak month of type B aortic dissection(Z=16.89>Z_0.05),and the peak time of the day was about 19:24(Z=12.67>Z_0.05),while the peak in group A was in January(Z=9.83>Z_0.05)and 18:04(Z=3.59>Z_0.05).The peak value of group B was in January(Z=7.27>Z_0.05)and 20:12(Z=11.45>Z_0.05).The temperature factor was analyzed by generalized additive model.It was found that the incidence of type B dissection in group A was easily affected by temperature difference（p=0.03,<p0.05）,but the lowest temperature was not statistically significant.The incidence of type B dissection in group B was related to the lowest temperature（p<0.01）,but not to the temperature difference.Conclusion:The incidence of acute type B aortic dissection has obvious seasonal and diurnal relationship,with more cases in winter and less in summer.January is the high incidence month of acute type B aortic dissection,and the peak time of onset is about19:20 o’clock in a day.The elderly over 60 years old are greatly affected by the temperature difference,and the patients under 60 years old are more likely to be affected by the lowest temperature.