Table 3.

Study quality grading criteria (grade 1 indicates the highest quality study)

Quality grading criteria
1	RCT with no methodological flaws
2	RCT with methodological flaws (validated questionnaires not used, insufficient sample size)
3	Randomised trial no control with no other methodological flaws
4	Randomised trial no control with methodological flaws (validated questionnaires not used, insufficient sample size)
5	Non-randomised controlled study with no methodological flaws
6	Non-randomised controlled study with methodological flaws (validated questionnaires not used, insufficient sample size)
7	One intervention group, no comparison