Use of Control Charts for Identifying Worsening Postoperative Mortality or Serious Morbidity Performance After Colectomy

Control charts are increasingly being used by hospitals as a tool for monitoring and improving health care quality. Our objective was to determine whether control charts of mortality or serious morbidity (M&M) rates after colectomy predict changes in outlier status for risk-adjusted M&M rates using data from a surgical registry, the American College of Surgeons National Surgical Quality Improvement Program. Control charts of monthly M&M rates for 95 hospitals were analyzed for indicators of a performance change in 2009 (vs 2008) using standard rules. Hospitals were also classified as having better, worse, or no change in outlier status for risk-adjusted M&M rates in 2009 (vs 2008). Agreement between these methods was fair (weighted κ = 0.379). There were no hospitals labeled as improving by one method and worsening by the other. Control charts predicted nonworsening performance well (specificity 0.866), but failed to identify 38.5% of hospitals with worsened outlier status. Although we did not demonstrate perfect agreement, our results suggest that these methods are measuring similar constructs of quality and are likely complementary uses of the same clinical data source.