Table 2

The methodological assessment of selected studies

		First author and year of publication
		Blasco, 1996⁸	Camp-Bruno, 1989⁶	Lewis, 1994⁷	Mier, 2000⁵	Reddihough, 1990⁹	Stern, 1997¹⁰	Owen, 1992¹¹
0 = other sub-item satisfied, 1 = item not performed nor described, 2 = item incompletely performed or inappropriately described, 3 = item performed or adequately described.
Research design		Cohort study	RCT	RCT	RCT	Cohort study	Cohort study	Experiment
Maximum possible sum score		54	60	60	60	54	54	60

Internal validity		Scores (minimally required score for specific item)
1	Randomisation	NA	3 (2)	2 (2)	1 (2)	NA	NA	3 (2)
2a	Homogeneity of the population	2 (3)	3 (2)	0 (2)	3 (2)	3 (3)	3 (3)	2 (2)
2b	Subgroup analysis	0 (3)	0 (2)	2 (2)	0 (3)	0 (3)	0 (3)	0 (2)
3	Adherence to therapy	1 (3)	3 (3)	1 (3)	1 (3)	1 (3)	3 (3)	1 (3)
4	Co-intervention control system	1	3	1	1	1	1	1
5	Standardised outcome measure	1 (2)	2 (2)	2 (2)	2 (2)	3 (2)	2 (2)	2 (2)
6	Repeated measurements	1	3	3	3	2	1	3
7	Intention to treat	NA	1 (3)	1 (3)	1	NA	NA	0 (3)

External validity
8	Inclusion/exclusion criteria	3 (3)	3 (3)	3 (3)	1	3 (3)	1 (3)	1 (3)
9	Description of intervention	3 (3)	3 (3)	3 (3)	3 (3)	3 (3)	3 (3)	3 (3)
10	Co-intervention checked	3	1	1	1	1	3	1
11	Outcome rates listed in text	1 (3)	3 (3)	3 (3)	3 (3)	3 (3)	1 (3)	3 (3)
12	Description and management of “lost to follow up”	3 (3)	3 (3)	3 (3)	3 (3)	1 (3)	3 (3)	1 (3)
13	Number of “lost to follow up”	3 (3)	3 (3)	3 (3)	3 (3)	1 (3)	3 (3)	1 (3)
14	Follow up period	3	1	1	3	3	2	3
15	Side effects	3	3	2	3	3	3	3

Data presentation
1	Adequate sample size	3 (3)	3 (3)	3 (3)	3 (3)	3 (3)	3 (3)	1 (3)
2	Mean	1 (3)	3 (3)	1 (3)	3 (3)	3 (3)	1 (3)	1 (3)
3	Standard deviation	1 (3)	3 (3)	1 (3)	3 (3)	3 (3)	1 (3)	1 (3)
4	Statistical method	1	3	1	3	3	3	3
5	Statistical analysis performed	1	3	3	3	3	3	3