Using the modified Jadad scale, studies were objectively assessed for quality and given 1 point when each of the following criteria was satisfied:
(1) Was the study described as randomized?
(2) Was the randomization protocol detailed and appropriate?
(3) Was the study described
as double-blind?
(4) Was the blinding process detailed and appropriate?
(5) Did the study have a control group?
(6) Was the control detailed and appropriate?
(7) Were there adequate exclusion criteria?
(8) Was the intervention used at a therapeutic dose?
(9) Was there a description of withdrawals and dropouts? and
(10) Were the data clearly and adequately reported? Using this scale, each trial was given a score between
0 and 10, with higher scores reflecting superior methodologic quality.