Table S1.

Quality assessment of the selected papers

Study	Year	Country	Clear description of purpose/objectives	Clear description of patient selection criteria	Clear description of INHBA detection	Predefinition of predictors and outcome measurements	Whether or not multivariate analysis and/or univariate analysis was used	Long enough follow-up period	Limitations considered	Quality (0–6)
Lee et al3	2014	Taiwan	Yes	No	Yes	No	Yes	Yes	Yes	5
Wang et al6	2016	People’s Republic of China	Yes	No	Yes	No	Yes	Yes	No	4
Okano et al1	2013	Japan	Yes	No	Yes	No	Yes	Yes	No	4
Oshima et al4	2014	Japan	Yes	No	Yes	No	Yes	Yes	No	4
Wang et al2	2012	People’s Republic of China	Yes	No	Yes	No	Yes	Yes	No	4
Katayama et al5	2017	Japan	Yes	No	Yes	No	Yes	Yes	No	4