Table 3.

Summary of the evidence quality grading using GRADE

Outcome	Quality assessment							Effect
	No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other onsiderations	SMD (95 %CI)	Quality
Sleep quality overall	8	RCT	Seriousa	Not serious	Not serious	Seriousb	Seriousc	−0.12 (−0.36, 0.13)	⊕⊕○○Low
Sleep quality VMS subgroup	3	RCT	Seriousa	Not serious	Not serious	Not serious	Seriousc	−0.54 (−0.91, −0.17)	⊕⊕⊕○Moderate

The GRADE working group grades of evidence are as follow: 1. High quality, future research is very unlikely to change the group’s confidence in the estimate of effect; 2. Moderate quality, further research is likely to have an important impact on the group's confidence in the estimate of effect and may change the estimate; 3. Low quality, further research is very likely to have an important effect on the group’s confidence in the estimate of effects and is likely to change the estimate; 4. Very low quality, the group is very uncertain about the estimate

^aThe quality was downgraded because there was overall poor reporting of blinding and allocation concealment

^bWide confidence intervals in our estimate effect limit conclusions

^cLarge numbers of studies do not contribute to sleep quality outcome, suggesting possible reporting bias

CI confidence interval, SMD standardized mean difference