Clinicopathological and prognostic value of hypoxia-inducible factor-1α in patients with bone tumor: a systematic review and meta-analysis

Table 4 The subgroups analysis for HIF-1α and DFS in patients with bone tumor

Subgroups	Number of studies	Case (n)	HIF-1α + (n)	HIF-1α + (%)	Pooled data			Test for heterogeneity
Subgroups	Number of studies	Case (n)	HIF-1α + (n)	HIF-1α + (%)	HR	95% CI	P value	P value	I² (%)
Region
Non-Asian	2	52	22	42	1.87	1.15–3.04	0.011	0.233	29.7
Asian	3	138	87	63	2.21	1.30–3.78	0.004	0.454	0
Histological type
Osteosarcoma	3	138	87	63	2.21	1.30–3.78	0.004	0.454	0
Chondrosarcoma	2	52	22	42	1.87	1.15–3.04	0.011	0.233	29.7
Case (n)
< 40	3	91	53	58	1.93	1.23–3.02	0.004	0.467	0
≥ 40	2	99	56	57	2.19	1.21–3.97	0.010	0.210	36.4
Follow-up (months)
< 100	1	50	29	58	1.90	1.01–3.58	0.047	NA	NA
≥ 100	4	140	80	57	2.08	1.34–3.21	0.001	0.368	5
Quality
High	2	88	58	66	3.22	1.19–8.68	0.021	0.368	0
Low	3	102	51	50	1.88	1.28–2.77	0.001	0.491	0

DFS disease-free survival, HIF-1α + hypoxia-inducible factor-1α expression, HR hazard ratio, CI confidence interval, NA not available due to single study

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