Table 1.

Evidence base included in the review

Category	Number of records
	Full papers	Abstracts
Initial search	16	19
records excluded	5	7
records included	11	12
Additional papers identified	2	0
Search update, new records	111	0
records excluded	106	0
records included	5	0
Level 1 clinical evidence	1	5
Level 2 clinical evidence	7	4
Level ≥3 clinical evidence	5	1
trials other than RCT	3	1
case studies	2	0
Economic evidence	0	1
Total records included	18	12

For definition of levels of evidence, see Editorial Information on inside back cover. RCT, randomized controlled trial.