Skip to main content

Table 4 The Mann–Whitney U test and Kruskal–Wallis H test analysis of covariates for LOS

From: Effects of seasonal and climate variations on in-hospital mortality and length of stay in patients with type A aortic dissection

Covariates Cases (%) M (P25,P75) χ2/Z P
Age (year)      
18–44 93 (23.0%) 18 (14, 24) 5.008 0.171
45–59 176 (43.6%) 18 (15, 26)   
60–74 124 (30.7%) 20.5 (16, 27)   
75–89 11 (2.7%) 21 (17, 26)   
Gender      
Male 90 (22.3%) 20 (15, 26) − 0.203 0.839
Female 314 (77.7%) 19 (15, 25)   
Hypertension      
No 113 (28.0%) 17 (14, 23) − 2.502 0.012
Yes 291 (72.0%) 20 (15, 27)   
Coronary heart disease      
No 396 (98.0%) 19 (15, 25) − 0.794 0.427
Yes 8 (2.0%) 25 (14, 43)   
Diabetes      
No 395 (97.8%) 19 (15, 25) − 0.107 0.915
Yes 9 (2.2%) 20 (16, 27)   
COPD      
No 401 (99.3%) 19 (15, 26) − 1.418 0.156
Yes 3 (0.7%) 14 (8, 20)   
Renal dysfunctiona      
No 322 (79.7%) 23 (18, 24) − 0.609 0.596
Yes 82 (20.3%) 16 (13, 26)   
Malperfusion syndromes      
No 332 (82.2%) 18 (15, 23) − 0.228 0.395
Yes 72 (17.8%) 18 (15, 22)   
Average minimum temperature on the day of onset (°C)      
 < 11.00 84 (20.8%) 19 (15, 27) 4.502 0.212
[11.00, 16.00] 117 (29.0%) 19 (15, 24)   
(16.00–23.00] 101 (25.0%) 18 (15, 23)   
 > 23.00 102 (25.2%) 22 (16, 31)   
Average daily temperature difference (°C)      
 < 5.00 77 (19.1%) 20 (14, 25) 2.100 0.552
[5.00, 7.00] 145 (35.9%) 18 (15, 26)   
(7.00, 9.00] 109 (27.0%) 19 (15, 24)   
 > 9.00 73 (18.1%) 20 (17, 27)   
Air Quality Index, AQI      
0–50 257 (63.6%) 19 (14, 25) 0.647 0.724
51–100 145 (35.9%) 19 (15, 26)   
101–150 2 (0.5%) 18 (17, 18)   
Season*      
Spring 79 (19.6%) 19 (15, 25) 7.975 0.046
Summer 76 (18.8%) 18 (14, 24)   
Autumn 123 (30.4%) 23 (16, 33)   
Winter 126 (31.2%) 19 (14, 25)   
Weekend surgery history      
No 327 (80.9%) 19 (15, 27) − 0.085 0.933
Yes 77 (19.1%) 21 (14, 24)   
Admission route      
Outpatient admission 14 (3.5%) 17 (15, 23) − 1.708 0.343
Emergency admission 390 (96.5%) 23 (18, 27)   
  1. aDefined as preoperative creatinine greater than 1.5 mg/dL
  2. *Season: autumn (21st September–20th December), winter (21st December–21st March), spring (22nd March–21st June 21), and summer (22nd June–20th September)