Methods
We reviewed all systematic reviews and meta-analyses in Cochrane
Database of Systematic Reviews from January 2016 through May 2021
(n=3,323). We identified 414(207x2) and 384 (192x2) pairs of original
and updated Cochrane reviews that assessed CoE and pooled treatment
effect estimates. We appraised CoE using the Grading of Recommendations
Assessment, Development and Evaluation (GRADE) method. We assessed the
difference in effect sizes between the original versus updated reviews
as a function of change in CoE, which we report as a ratio of odds ratio
(ROR). We compared ROR generated in the studies that changed CoE from
very low/low (VL/L) to moderate/high (M/H) vs. MH/HVL/L. We also
assessed the heterogeneity and inconsistency (using the tau andI 2 statistic), the change in precision of
effect estimates (by calculating the ratio of standard errors) (seR),
and the absolute deviation in estimates of treatment effects (aROR).