Table 2.

Subgroup analyses of associations between hypertension and deep vein thrombosis after orthopedics surgery

Classification	Item	N	I 2 (%)	P	Model	OR [95 % CI]
Regional distribution	Western China	4	0	0.9498	F	3.89 [2.85–5.30]
	Central China	3	71.5	0.0298	R	2.70 [1.32–5.52]
	Eastern China	9	53.9	0.0268	R	3.95 [2.92–5.33]
The proportion of including	N < 500	13	0	0.8881	F	3.37 [2.63–4.31]
	N ≥ 500	3	91.5	<0.0001	R	2.23 [1.14–4.34]

OR odds ratio, R random effects model, F fixed effect model