Table 2 Subgroup analysis of VTE in hospital (after IPTW)

Age

 18–59 years

1/528 (0.2)

4/500 (0.8)

0.32 (0.04–2.89)

0.311

 ≥ 60 years

0/649 (0.0)

6/752 (0.8)

–

< 0.001

 60–79 years

0/518 (0.0)

6/656 (0.9)

–

< 0.001

 ≥ 80 years

0/131 (0.0)

0/96 (0.0)

–

–

 Weight ≤ 50 kg

0/125 (0.0)

0/135 (0.0)

–

–

Impairment of renal function

 Normal

1/541 (0.2)

5/469 (1.1)

0.23 (0.01–1.43)

0.179

 Light

0/242 (0.0)

1/261 (0.4)

–

< 0.001

 Moderate

0/75 (0.0)

1/68 (1.5)

–

< 0.001

Complication

 Diabetes mellitus

0/93 (0.0)

0/111 (0.0)

–

–

 Hypertension

0/402 (0.0)

4/451 (0.9)

–

< 0.001

 Tumor

0/35 (0.0)

0/32 (0.0)

–

–

 Anemia

0/69 (0.0)

0/49 (0.0)

–

–

Different types of surgery^a

 Major orthopedic surgery

1/625 (0.2)

8/780 (1.0)

0.19 (0.02–1.54)

0.121

 Other trauma surgery

0/500 (0.0)

2/436 (0.5)

–

< 0.001

 No surgery

0/72 (0.0)

0/54 (0.0)

–

–

Different types of surgery^b

 Hip and knee replacement

1/456 (0.2)

8/654 (1.2)

0.22 (0.03–1.74)

0.150

 Trauma surgery

0/673 (0.0)

2/583 (0.3)

–

< 0.001

 No surgery

0/72 (0.0)

0/54 (0.0)

–

–

Premedicate

 > 0 h

0/476 (0.0)

1/337 (0.3)

–

 < 0.001

 > 24 h

0/450 (0.0)

1/308 (0.3)

–

 < 0.001

Different days of administration

 0–5 days

0/636 (0.0)

2/630 (0.3)

–

< 0.001

 6–9 days

1/376 (0.3)

7/450 (1.6)

0.17 (0.02–1.44)

0.106

 10–15 days

0/120 (0.0)

1/132 (0.8)

–

< 0.001

 16–35 days

0/41 (0.0)

0/37 (0.0)

–

–

 > 35 days

0/4 (0.0)

0/2 (0.0)

–

–

Duration of surgery

 ≤ 45 min

0/40 (0.0)

0/32 (0.0)

–

–

 > 45 min

1/1029 (0.1)

9/1092 (0.8)

0.14 (0.02–1.11)

0.063

Surgery and impairment of renal function

 Major orthopedic surgery and moderate

0/43 (0.0)

1/48 (2.1)

–

< 0.001

 Other trauma surgery and moderate

0/25 (0.0)

0/13 (0.0)

–

–