Table 3.

Risk of bias and methodologic quality assessment of included studies

Study	Rating based on Cochrane risk-of-bias tool							Downs and Black checklist
										Internal validity
	Sequence generation	Allocation concealment	Blinding	Incomplete outcome data	Selective outcome reporting	Other bias	Summary	Reporting	External validity	Bias	Confounding	Power	Total
								/11	/3	/7	/6	/5	/32
RCTs or subgroup of RCTs
McIntyre et al. 2006a	Low	Low	High	Low	Low	Low	Low	10	3	6	5	0	24
Lacroix et al. 2007a	Low	Low	High	Low	Low	Low	Low	11	3	5	6	0	25
Naidech et al. 2010	Low	Low	Unclear	Low	Low	Low	Low	7	1	6	5	2	21
Nonrandomized studies
Flückiger et al. 2010								5	3	6	4	0	18
George et al. 2008								9	2	4	3	0	18
Warner et al. 2010								9	2	6	3	1	21

RCT randomized controlled trial. ^aCochrane risk-of-bias tool applied on initial RCT.