Table 5.

Subgroup analysis of the association between circulating adiponectin levels and HCC risk

Variable	Included studies	Test of association			Test of heterogeneity
		SMD	95%CI	P-value*	Modal	P-value	I2
HCC vs Healthy controls
Overall	[24, 29, 31, 34–36, 40]	1.57	0.37, 2.76	0.010	RE	0.000	99.0%
HCC(unreported reason) vs Healthy controls	[24, 31, 34, 35]	1.88	−0.31, 4.08	0.092	RE	0.000	99.5%
Viral HCC vs Healthy controls	[29, 36, 40]	1.11	0.44, 1.78	0.001	RE	0.000	90.8%
HCC vs Cirrhosis
Overall	[27, 33, 36, 40]	−0.51	−1.30, 0.29	0.213	RE	0.000	93.9%
Viral cirrhotic HCC vs Viral cirrhosis	[27, 33]	−0.37	−1.80, 1.05	0.607	RE	0.000	95.9%
HCV-related HCC vs HCV-related cirrhosis	[33, 40]	−1.22	−1.54, −0.90	0.000	FE	0.531	0.0%
HCC vs Chronic hepatitis
Overall	[28, 34, 36, 38, 39, 43]	0.10	−0.80, 1.00	0.826	RE	0.000	98.4%
HCC(unreported causes) vs Chronic hepatitis C	[34, 39]	− 0.48	−5.71, 4.75	0.857	RE	0.000	99.6%
HCV-related HCC vs Chronic hepatitis C	[28, 43]	0.08	−0.22,0.38	0.599	RE	0.068	70.0%
Viral HCC vs Chronic viral hepatitis	[28, 36, 38, 43]	0.35	−0.08, 0.78	0.108	RE	0.000	91.8%
Ethnicity
Asian	[28, 29, 35, 36, 38, 43]	0.31	0.02, 0.61	0.036	RE	0.000	88.3%
Caucasian	[24, 27, 31]	0.73	0.11, 1.35	0.022	RE	0.000	90.3%
African	[33, 34, 39, 40]	−0.32	−2.93, 2.29	0.811	RE	0.000	99.5%
Sample size
< 200	[27, 31, 33, 39, 40, 43]	0.76	0.03, 1.50	0.042	RE	0.000	98.5%
≥ 200	[24, 28, 29, 34–36, 38]	−0.40	−1.34, 0.54	0.403	RE	0.000	97.1%
Mean age
< 60	[27–29, 33, 34, 36, 39, 40]	0.10	−0.85, 1.05	0.833	RE	0.000	98.8%
≥ 60	[24, 35, 43]	0.13	−0.14, 0.39	0.362	RE	0.037	69.7%
Study design
Nested Case-control	[24, 27, 28, 35, 38]	0.25	0.14, 0.36	0.000	EE	0.585	0.0%
Case-control	[29, 34, 40, 43]	0.84	−0.74, 2.12	0.298	RE	0.000	99.2%
Cross-sectional	[33, 36, 39]	−1.10	−3.46, 1.26	0.361	RE	0.000	99.0%
Sample source
Serum	[24, 27, 29, 31, 33–36, 39, 40, 43]	0.23	−0.51, 0.97	0.540	RE	0.000	98.5%
Plasma	[28, 38]	0.23	0.08, 0.38	0.003	FE	0.795	0.0%
Assay method
ELISA	[24, 27, 28, 31, 33, 35, 36, 38–40, 43]	−0.03	−0.45, 0.40	0.901	RE	0.000	95.7%
Non-ELISA	[29, 34]	1.75	−0.75, 4.26	0.170	RE	0.000	99.4%
Alanine aminotransferase
< 70 U/L	[28, 33, 36, 40, 43]	0.00	−0.53, 0.53	0.992	RE	0.000	94.8%
≥ 70 U/L	[27, 34, 39]	0.08	−2.96, 3.12	0.958	RE	0.000	99.5%
Albumin
< 3.5 g/dl	[33, 34, 40]	0.62	−1.98, 3.22	0.639	RE	0.000	98.5%
≥ 3.5 g/dl	[27, 28]	0.24	0.09,0.40	0.002	RE	0.000	99.4%

RE Random-effects model, FE Fixed-effects model, HCC Hepatocellular carcinoma, HCV hepatitis C virus

*Statistically significant results were shown in bold