“…All of the studies had a clearly stated aim, prospective collection of data, end points appropriate to the aim of the study, loss to follow-up <5%, and contemporary groups. Six studies included consecutive patients 6, 7, 17, 29, 30, 32 , two stated they had unbiased assessments of study end points 6, 7 , one had a prospective calculation of the study size 17 , three had adequate control groups 6, 7, 29 , five had baseline equivalence of groups 6, 7, 17, 29, 31 , and five had adequate statistical analyses 7, 17, 29, 30, 32 . The lowest score was 16 31 , and the highest was 22 7 .…”