The Effectiveness and Safety of Mesenchymal Stem Cells in the Treatment of Osteoarthritis: A Systematic Review and Meta-analysis of 28 Randomized Controlled Trials

Table 2

Quality of evidence.

Outcomes	Illustrative comparative risks(95% CI)		Relative effect (95% CI)	No of participants; (studies)	Quality of the evidence; (GRADE)	Comments
	Assumed risk	Corresponding risk
	Control	Adverse event
WOMAC pain-12 months		The mean WOMAC pain-12 months in the intervention groups was 4.29 lower (7.12 to 1.47 lower)		286 (9 studies)	⊕⊕⊝⊝ low^1,2
VAS-12 months		The mean VAS-12 months in the intervention groups was 1.77 lower (2.43 to 1.12 lower)		669 (19 studies)	⊕⊝⊝⊝ very low^1,2,3
WOMAC stiffness-12 months		The mean WOMAC stiffness-12 months in the intervention groups was 0.99 lower (1.95 to 0.03 lower)		286 (9 studies)	⊕⊕⊝⊝ low^1,2
WOMAC physical function-12 months		The mean WOMAC physical function-12 months in the intervention groups was 3.26 lower (5.91 to 0.61 lower)		254 (8 studies)	⊕⊕⊕⊝ moderate^1
Adverse events	Study population		RR 1.2 (0.97 to 1.48)	706; (17 studies)	⊕⊕⊕⊝ moderate^1
	259 per 1000	310 per 1000 (251 to 383)
	Moderate
	125 per 1000	150 per 1000 (121 to 185)

The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; RR: risk ratio; GRADE Working Group grades of evidence. High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. ¹Downgraded one level due to serious risk of bias (random sequence generation, allocation concealment, blinding, and incomplete outcomes), and most of the data comes from the RCTs with moderate risk of bias. ²Downgraded one level due to the probably substantial heterogeneity. ³Downgraded one level due to the potential publication bias.