Table 4 Rating the quality of evidence using the GRADE methodology
From: The quadrivalent HPV vaccine is protective against genital warts: a meta-analysis
Num-ber of studies | Study design | Initial level of evi-dence | Evidence components | Downgrade/upgrade of evidence | Notes | Final level of evidence |
|---|---|---|---|---|---|---|
8 | RCT | high | Risk of bias | – | – | ⨁⨁⨁O MODERATE |
Heterogeneity | – | – | ||||
Indirectness | downgrade by 1 | groups with different background risks | ||||
Imprecision | – | – | ||||
Publication bias | – | – | ||||
8 | time-trend analysis | low | Risk of bias | – | – | ⨁⨁OO LOW |
Heterogeneity | downgrade by 1 | low p value | ||||
Indirectness | – | – | ||||
Imprecision | upgrade by 1 | high number of participants, narrow CI | ||||
Publication bias | – | – |