Increasing hospital volume contributes to decreased mortality for certain procedures
WEDNESDAY, June 1 (HealthDay News) -- Mortality rates for certain high-risk surgical procedures have decreased in the United States, which is partially due to increased market concentration and hospital volume, according to a study published in the June 2 issue of the New England Journal of Medicine.
Jonathan F. Finks, M.D., from the University of Michigan in Ann Arbor, and colleagues examined trends in hospital volume and market concentration for patients undergoing esophagectomy, pancreatectomy, lung resection, cystectomy, repair of abdominal aortic aneurysm (AAA), coronary-artery bypass grafting (CABG), carotid endarterectomy, or aortic-valve replacement (from 1999 through 2008). The effects of hospital volume and market concentration (defined as the proportion of Medicare patients undergoing surgery in the top decile of hospitals per volume per year) on mortality were assessed over time, adjusting for case mix.
The investigators found that the average hospital volumes for lung, esophagus, pancreas, and bladder cancer resections, and AAA repair rose substantially; and, for aortic-valve replacement, the volume rose slightly. Hospital volumes fell for CABG and carotid endarterectomy. Increased hospital volumes could be attributed to a higher number of cases nationwide, an increasing market concentration, or both. Mortality rates decreased for all eight procedures, varying from a relative decrease of 8 percent for carotid endarterectomy to 36 percent for AAA repair. Higher hospital volumes accounted for a large portion of the decrease in mortality for pancreatectomy (67 percent), cystectomy (37 percent), and esophagectomy (32 percent), but not for the other procedures.
"The contribution of increasing hospital volume to declining mortality varied considerably according to procedure," the authors write.