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Are High-Quality Cardiac Surgeons Less Likely to Operate on High-Risk Patients?

Physician scorecards have been a highly touted means to improve healthcare quality. One example is NY state’s coronary artery bypass graft (CABG) Surgery Reporting System. One side effect of scorecards is that surgeons may choose to operate on healthier patients in order to maximize their scorecard grade. In fact, over 60 percent of NY cardiothoracic surgeons reported refusing to operate on high risk patients on at least one occasion (Burack et al. 1999).

A paper by Glance et al. (HSR 2007) investigates whether or not high-quality cardiac surgeons are less likely to operate on high-risk patients. The paper uses a data set with over 57,000 patients treated by 189 surgeons. The authors first estimate a regression as follows:

  • log[pi/(1-pi)] = α + Σβkxkij + ΣλjPj

The equation above estimates the predicted probability of the ith patient treated by the jth surgeon with risk factors xkij. The mortality of each patient if they are treated by the average surgeon is

  • log[pn/(1-pn)] = α + Σβkxki

To determine the surgeon’s quality the authors used the observed to expected mortality rate.


The paper finds that high quality surgeons actually treat higher risk patients. This finding is reassuring for those who favor medical scorecards. The authors due note some issues with the paper. For instance, one must be sure that the risk adjustment calculation is correct, and high-quality surgeons may be miscoding patients more frequently as high-risk. Another explanation could be that high quality surgeons have more experience and are closer to the end of their careers so they care less about scorecards and more about informal reputations. However, as young surgeons age and have been conditioned to believe that scorecards matter, this finding that high quality surgeons treat high risk patients may not hold in the long run. Nevertheless, the study is straightforward, clear and assuages some fear of patient selection by doctors operating under a scorecard system.