Table 1 . Baseline characteristics of studies included in the meta-analysis .

Reference number	Study design	Country	Patients number	Age (years)	Male (%)
6	Co, P	Norway	173	48.0±16	69
7	Co, P	Norway	124	48.0±15	75
9	Co, R	Romania	177	42.8±12.2	66
13	Co, R	Taiwan	43	44.2±10.4	51
14	Co, P	Norway	494	48.8±15.1	65
15	Co, R	Poland	308	47.3±12.7	60
16	Co, R	Japan	70	45.0±11.1	53

Co: cohort study; P: prospective; R: retrospective