Risk-adjusted sequential probability ratio test control chart methods for monitoring operator and institutional mortality rates in interventional cardiology
Received 6 February 2007; accepted 20 August 2007. published online 08 October 2007.
Background
The objective of this study was to evaluate risk-adjusted sequential probability ratio test control charts for the detection of significant discrepancies between institution or individual interventional cardiologist postprocedural mortality rates and national or local event rate expectations.
Methods
Eight thousand nine hundred forty-two percutaneous coronary interventional procedures were performed by 27 operators between January 1, 2002, and November 30, 2006. The institution-based evaluation included all procedures, and the individual-based evaluations included 8750 procedures performed by 18 operators who had each done at least 100 PCI procedures. Risk-adjusted sequential probability ratio test control charts were developed to assess whether the odds ratios (ORs) for death were >2.0 for α = β = 0.10. The American College of Cardiology 1.1 prediction model was used to risk-adjust both the institution and individuals, and an additional local model was used for individuals.
Results
After national risk adjustment, the local institution did not show mortality of more than a 1.5 OR. Two operators had a >2.0 mortality OR after national risk adjustment, and one of those remained elevated after local risk adjustment. Of 18 operators, 10 had insufficient data to allow us to accept or reject the hypothesis of increased risk.
Conclusions
The local institution performed within national expectations, but 1 operator was identified as having poor performance, which prompted an in-depth review of that operator's cases. The review revealed that the operator had an unusually high number of patients who presented with risk factors not included in the risk-adjustment models. This study highlights the utility of risk-adjusted sequential probability ratio test as a method for outcomes monitoring and quality control in interventional cardiology.
aDecision Systems Group, Department of Radiology, Brigham and Women's Hospital, MA
bDivision of General Medicine, Brigham and Women's Hospital, Boston, MA
cDivision of Cardiology, Brigham and Women's Hospital, Boston, MA
dDivision of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA
Reprint requests: Michael E. Matheny, MD, MS, MPH, Division of General Internal Medicine and Public Health, Vanderbilt University, Suite 6000, Medical Center East North Tower, 1215 Twenty-first Avenue South, Nashville, TN 37232-8300.
This research was supported in part by grants 1-T15-LM-07092 and R01-LM-08142-04 from the National Library of Medicine, Bethesda, MD of the National Institutes of Health, Bethesda, MD. The authors have no conflict of interests to disclose.
ABSTRACT