Outcomes and Effectiveness Research

Patient outcomes are better than hospital volume for identifying high-quality bariatric surgery centers

Surgery to help severely obese patients lose weight (bariatric surgery) is a rapidly growing field. Hospital accreditation programs and insurers have used a hospital's volume of such operations to identify high-quality bariatric surgery centers. However, a new study recommends that accreditation groups and insurers switch to direct measurement of outcomes, such as morbidity (problems following bariatric surgery), in evaluating the quality of these centers. Examples of morbidities include respiratory failure, collapsed lungs, heart attacks, kidney failure, and shock.

Using morbidity, adjusted for patient risk factors for postsurgical problems, to rank hospitals during an initial 2-year period predicted a 4.5-fold difference in risk-adjusted morbidity between the best-performing and worst-performing quartile of hospitals during a 2-year followup period. Ranking hospitals based only on their volume of bariatric surgeries predicted only a 1.9-fold difference in risk-adjusted morbidity between the best-performing and worst-performing quartiles. Risk-adjusted morbidity accounted for 83 percent of hospital-level variation in morbidity compared with only 21 percent of this variation using procedure volume.

The researchers used data from the State Inpatient Database for New York, 2003-2006, which is maintained as part of the AHRQ Healthcare Cost and Utilization Project. The researchers identified all adults who underwent gastric bypass surgery in New York State during this period. They calculated volumes of gastric bypass surgeries and rates of risk-adjusted morbidities at each hospital for 2003-2004. The hospitals were divided into quartiles based on either volume or morbidity during the initial 2-year period, and the researchers calculated risk-adjusted morbidity rates during 2004-2006 for each quartile. The study was funded in part by the Agency for Healthcare Research and Quality (HS17765).

More details are in "Identifying high-quality bariatric surgery centers: Hospital volume or risk-adjusted outcomes?" by Justin B. Dimick, M.D., M.P.H., Nicholas H. Osborne, M.D., Lauren Nicholas, Ph.D., and others in the December 2009 Journal of the American College of Surgeons 209(12), pp. 702-706.

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