Table 3. Sensitivity analysis of high-quality studies to determine the prognostic value of glycolysis markers in HNSCC patients.

	Variable	Study NO.	Sample size	HR [95% CI]	P value	Heterogeneity
						I2 (%)	P value
OS	Overall	15	1596	2.14 [1.78, 2.57]	<0.001	15	0.29
	Ethnicity
	Asian	10	949	2.50 [1.91, 3.27]	<0.001	0	0.76
	Caucasian	5	647	2.04 [1.35, 3.08]	<0.001	52	0.08
	Glycolysis marker
	GLUT1	7	748	1.92 [1.52, 2.43]	<0.001	22	0.26
	MCT4	1	99	3.64 [1.60, 8.29]	0.002	-	-
	HK2	2	277	2.04 [1.11, 3.78]	0.02	0	0.77
	PKM2	3	311	2.92 [1.85, 4.59]	<0.001	0	0.41
	GLUT4	2	161	1.93 [0.97, 3.81]	0.06	61	0.11
	Tumor location
	OSCC	9	909	2.69 [2.07, 3.48]	<0.001	0	0.52
	NPC	2	203	1.72 [0.95, 3.11]	0.07	0	1
	LSCC	1	49	3.46 [0.73, 16.25]	0.12	-	-
	Oropharyngeal SCC	1	274	1.50 [1.05, 2.15]	0.026	-	-
	Sample size
	Large	9	1248	2.10 [1.71, 2.59]	<0.001	0	0.44
	Small	6	348	2.26 [1.53, 3.36]	<0.001	41	0.13
DFS	Overall	7	696	1.55 [0.97, 2.47]	0.07	47	0.08
	Ethnicity
	Asian	3	270	2.32 [1.45, 3.70]	<0.001	0	0.40
	Caucasian	4	426	1.08 [0.68, 1.71]	0.76	29	0.24
	Glycolysis marker
	GLUT1	3	318	1.59 [0.92, 2.74]	0.10	33	0.23
	MCT4	1	99	3.42 [1.51, 7.78]	0.003	-	-
	HK2	1	97	1.01 [0.50, 2.05]	0.98	-	-
	PKM2	1	111	2.53 [1.01, 6.37]	0.008	-	-
	GLUT4	1	71	0.78 [0.32, 1.92]	0.59	-	-
	Tumor location
	OSCC	4	431	2.09 [1.33, 3.31]	0.002	45	0.14
	Sample size
	Large	5	565	1.75 [0.94, 3.27]	0.08	53	0.07
	Small	2	131	1.21 [0.69, 2.13]	0.50	35	0.22