Data synthesis and statistical analysis
Meta-analysis was carried out comparing the effect of all QI
interventions on the performance of rarely appropriate echocardiography
testing and also analyzed based on short-term (< 3 months) and
long-term (>3 months) effects. Subgroup analysis was
performed for specific QI interventions, including Feedback Tool,
Education Tool, or Decision Support Tool. Statistical analysis was
performed using comprehensive meta-analysis software.9The extent of heterogeneity was determined by I2 (ranging from 0% to
100%). Due to high heterogeneity, we used a random-effects model to
examine the effect and outcomes, which were presented as odds ratio (OR)
with Z-value. Statistical significance was considered with a P-value
< 0.05 and all tests were 2-sided. Funnel plot of standard
error by log HR was created to qualitatively assess publication bias.