Table 2.

Methodological quality of meta-analyses.

Questions	Supported by industry	Non-profit support or no support	P value*	Undeclared support
	(N = 10)	(N = 18)		(N = 11)
1. Were the search methods used to find evidence on the primary question stated?	6	18	0.02	6
2. Was the search for evidence reasonably comprehensive?	4	17	<0.01	6
3. Were the criteria used for deciding which studies to include reported?	5	17	0.03	10
4. Was bias in the selection of studies avoided?	1	12	0.01	3
5. Were the criteria used for assessing the validity of the included studies reported?	3	15	0.02	5
6. Was the validity of all studies referred to in the text assessed using appropriate criteria?	1	10	0.04	1
7. Were the methods used to combine the findings of the relevant studies reported?	9	17	1.00	10
8. Were the findings of the relevant studies combined appropriately?	7	16	0.46	8
9. Were the conclusions made by the author(s) supported by the data reported?	9	15	1.00	9
Overall quality (1–7) (median score)	2.5	6	<0.01	3

Number of meta-analyses that obtained an affirmative answer to the questions of the Oxman and Guyatt index; and median overall quality score.

* Supported by industry vs non-profit or no support.