“…Eighty-two non-comparative studies [2, 4, 7, 8, 12, 15, 17, 20, 22, 23, 25, 29, 32, 33, 36-41, 45, 46, 50-52, 54, 55, 57, 58, 64, 66, 67, 72, 73, 75, 76, 82, 86-90, 95, 97, 99, 102, 103, 111, 113, 117, 118, 120, 122-124, 126-128, 130, 133, 137, 139, 143, 146-154, 158, 161, 162, 165-167, 171, 172, 174, 176] were at high risk of bias and only six [56,70,71,78,92,104] were at low risk of bias; 34 comparative studies [5, 10, 13, 18, 19, 21, 34, 35, 43, 44, 49, 59, 60, 69, 77, 79-81, 91, 93, 94, 98, 106-109, 125, 144, 155, 156, 160, 170, 173, 175] were at high risk of bias, while only 11 [1,9,14,30,61,65,105,129,134,138,177] were at low risk of bias.…”