“…Figure 1 shows the PRISMA flow chart for the study screening and selection process in this research. Twenty-three trials including 19 retrospective studies [21] , [23] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] and 4 prospective studies [22] , [42] , [43] , [44] , enrolling 117735 study subjects ultimately met our criteria ( Figure 1 ). Six studies were performed in USA [25] , [26] , [29] , [31] , [35] , [40] , five in Italy [27] , [28] , [38] , [39] , [42] , four in Spain [27] , [36] , [37] , [43] , three in United Kingdom [22] , [33] , [34] , two in China [23] , [30] , one in France [41] , one in India [32] and one in Australia [21] .…”