Table 1 The basic characteristics of the study patients

Number of patients

4479

63778

Age (years)

<0.0001

 Median

81

80

 IQR

73–86

71–86

 Category [n (%)]

 <65

487 (10.9)

9898 (15.5)

 65–74

802 (17.9)

11598 (18.2)

 ≥75

3190 (71.2)

42282 (66.3)

Male [n (%)]

2351 (52.5)

33981 (53.3)

0.305^a

NYHA [n (%)]

<0.0001^a

 I

254 (5.7)

5411 (8.5)

 II

1235 (27.6)

19168 (30.1)

 III

1652 (36.9)

22164 (34.8)

 IV

1338 (29.9)

17035 (26.7)

Charlson Comorbidity Index

<0.0001

 Median

2

2

 IQR

1–3

1–3

 Category [n (%)]

 ≤1

1181 (26.4)

19906 (31.2)

 2

1187 (26.5)

17992 (28.2)

 3

1025 (22.9)

13543 (21.2)

 ≥4

1086 (24.3)

12337 (19.3)

LOS

0.571

 Median

19

19

 IQR

12–29

12–29

BMI

<0.0001

 Median

21.7

22.3

 IQR

19.2–24.4

19.7–25.2

Hospital volume

0.914

 Median

104

105

 IQR

70–147

68–150

 Category [n (%)]

 ≤68

1079 (24.1)

16116 (25.3)

 69–150

2356 (52.6)

31904 (50.0)

 ≥151

1044 (23.3)

15758 (24.7)