GRADE assessment
pain
ADVERSE EVENTS, ADVERSE EVENT
We use the GRADE approach to assess evidence for each important outcome and present the summary findings for all combinations of MSCs therapy and control interventions in the included RCTs and non-RCTs. These treatments were evaluated as clinical activity, measures of response by the ACR scale, and safety of therapy with MSCs. The grade of certainty of evidence for clinical activity outcome measures was considered high to low. The quality of evidence was downgraded for risk of bias, inconsistency, and imprecision of the results. Due to the few studies (n < 10) in the meta-analysis, the publication bias could not be excluded because the test power is usually too low to distinguish chance from real asymmetry. The certainty of evidence for DAS28-ESR outcomes was high (outcome measures were reported in one RCT). Certainty of the subscales of WOMAC as pain, function, stiffness outcomes was moderate (outcome measures were reported in one RCT); certainty for VAS, DAS28, and HAQ outcomes was high to low (outcome measures were reported in two RCTs). Certainty of evidence for measure of response outcomes as patients reaching ACR 20,50,70 was considered high to low (outcome measures were reported in two RCTs). Certainty of evidence for the safety of treatments: Adverse events (serious and non-serious adverse events) were low with inconsistency (1 level) and imprecision (1 level).The evidence was downgraded for inconsistency and imprecision from 1 to 2 levels. None of the outcomes were upgraded based on risk of bias (see 