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Table 1 The Chi-square test of covariates for in-hospital mortality

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

Covariates Survive Death χ2 P
Age (year)     
18–44 91 (97.8%) 2 (2.2%) 3.057 0.383
45–59 165 (93.8%) 11 (6.3%)   
60–74 119 (96.0%) 5 (4.0%)   
75–89 11 (100.0%) 0 (0.0%)   
Gender     
Male 300 (95.5%) 14 (4.5%) 0.000 1.000
Female 86 (95.6%) 4 (4.4%)   
Hypertension     
No 107 (94.7%) 6 (5.3%) 0.269 0.604
Yes 279 (95.9%) 12 (4.1%)   
Coronary heart disease     
No 357 (96.0%) 15 (4.0%) 20.381  < 0.000
Yes 24 (75.0%) 8 (25.0%)   
Diabetes     
No 378 (95.7%) 17 (4.3%) 0.958 0.328
Yes 8 (88.9%) 1 (11.1%)   
COPD     
No 383 (95.5%) 18 (4.5%) 0.141 0.707
Yes 3 (100.0%) 0 (0.0%)   
Renal dysfunctiona     
No 300 (93.2%) 22 (6.8%) 24.230  < 0.000
Yes 61 (74.4%) 21 (25.6%)   
Malperfusion syndromes     
No 303 (91.3%) 29 (8.7%) 4.082 0.043
Yes 60 (83.3%) 12 (16.7%)   
Average minimum temperature on the day of onset (°C)     
 < 11.00 83 (98.8%) 1 (1.2%) 7.208 0.066
[11.00, 16.00] 112 (95.7%) 5 (4.3%)   
(16.00–23.00] 98 (97.0%) 3 (3.0%)   
 > 23.00 93 (91.2%) 9 (8.8%)   
Average daily temperature difference (°C)     
 < 5.00 75 (97.4%) 2 (2.6%) 1.848 0.605
[5.00, 7.00] 136 (93.8%) 9 (6.2%)   
(7.00, 9.00] 105 (96.3%) 4 (3.7%)   
 > 9.00 70 (95.9%) 3 (4.1%)   
Air Quality Index, AQI     
0–50 244 (94.9%) 13 (5.1%) 0.658 0.720
51–100 140 (96.6%) 5 (3.4%)   
101–150 2 (100.0%) 0 (0.0%)   
Spring 74 (93.7%) 5 (6.3%) 9.225 0.026
Season*     
Summer 69 (90.8%) 7 (9.2%)   
Autumn 108 (87.8%) 15 (12.2%)   
Winter 123 (97.6%) 3 (2.4%)   
Weekend surgery history     
No 313 (95.7%) 14 (4.3%) 0.122 0.727
Yes 73 (94.8%) 4 (5.2%)   
Admission route     
Outpatient admission 13 (92.9%) 1 (7.1%) 0.000 0.496
Emergency admission 372 (95.4%) 18 (4.6%)   
  1. *Season: autumn (21st September–20th December), winter (21st December–21st March), spring (22nd March–21st June 21), and summer (22nd June–20th September)
  2. aDefined as preoperative creatinine greater than 1.5 mg/dL