Hospital Volume Not Best Indicator of Bypass Quality

A study has found that for patients undergoing coronary artery bypass graft (CABG) surgery, hospital volume may not be an adequate indicator of quality, contrary to some recent recommendations. The finding was reported in the January 14, 2004, issue of The Journal of the American Medical Association (JAMA).

Researchers found that the median annual hospital volume for isolated CABG procedures was 253, with 82% of centers performing fewer than 500 procedures per year and an overall mortality rate of 2.66%. After adjusting for patient risk and clustering effects, mortality rates decrease with increasing hospital volume but this association was not observed in patients younger than 65 or in those at low operative risk and was confounded by surgeon volume. Closure of up to 100 of the lowest-volume hospitals was estimated to avert less than 1% of deaths from bypass surgery.

"We found that, compared with high-volume hospitals, low-folume hospitals tended to operate on patients with higher risk and under more emergent conditions,” the authors write. "Hospital volume has generally poor predictive accuracy as a means of identifying hospitals with significantly better or worse CABG mortality rates. Using volume as a sole referral criterion for selecting a provider would unfairly defer cases from nearly half of very-low volume centers with outcomes equal or better than overall mortality results.”

The study suggests that hospital CABG surgery volume is best considered as a surrogate for quality in a setting where other more-direct process and outcome assessments are not available, conclude the researchers. The study, involving 267,089 procedures at 439 U.S. hospitals, was conducted by Eric D. Peterson, M.D., Ph.D., and colleagues at the Duke Clinical Research Institute (Durham, NC, USA).




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Duke Clinical Research Institute