Seasonal and daily variations in the occurence and outcomes of acute Stanford type A dissections: a retrospective single-center study

Abstract

Background To investigate the seasonal, monthly, and daily distributions of the incidence of Stanford type-A acute aortic dissection (TAAAD) and identify seasonality in the duration of hospital stay and in-hospital mortality of TAAAD in south-eastern China. Methods We enrolled patients diagnosed with TAAAD between 1 June 2017 and 31 May 2021. Participants were divided into seasonal, monthly, and daily groups according to the need for analysis. Analysis of variance was applied to compare the number of TAAAD in different seasons, months, and days. χ2 test was used to compare in-hospital mortality among the four groups. Non-parametric methods were used for all comparisons of the duration of hospital stay. Univariate logistic and multivariable logistic regression analyses were performed to assess the duration of hospital stay. Results Of the 485 patients, 154 were diagnosed in winter (31.8%), 115 in spring (23.7%), 73 in summer (15.1%), and 143 in autumn (29.5%). The daily, monthly, and seasonal distributions of TAAAD were significantly different (P = 0.04, P < 0.01, and P < 0.01, respectively). This study did not identify any significant decrease in maximal, mean, or minimum temperatures between the three days before TAAAD and the day of TAAAD. No seasonal variations associated with in-hospital mortality was observed (P = 0.89). However, significant differences were observed in the seasonal distribution of the duration of hospital stay for TAAAD [winter was 17.0 (4.0–24.0) days, spring was 20.0 (14.0–29.0) days, summer was 20.0 (12.5–31.0) days, and autumn was 20.0 (13.0–30.0) days, P < 0.01]. Multiple factor analysis showed that winter was the independent risk factor for the increased duration of hospital stay. The odds ratio for winter was 2.21 (1.46, 3.33, P < 0.01). Conclusions Our study confirmed that the incidence of TAAAD exhibits seasonal, monthly, and daily variations in south-eastern China. Moreover, the daily incidence of TAAAD is higher on weekdays than that on weekends.