"The Medicare centers of excellence policy was associated with a 4.7 percentage point (17 percent) decline in the proportion of Medicare patients receiving bariatric surgery who were non-white," said Lauren Hersch Nicholas, PhD, MPP, lead author of the letter and an assistant professor with the Bloomberg School's Department of Health Policy and Management. "It appears that a policy intended to improve patient safety had the unintended consequence of reduced use of bariatric surgery by minority Medicare patients."

Hospitals are recognized as centers of excellence if they submitted data to a registry, have adequate protocols for care of morbidly obese patients, and perform at least 125 bariatric procedures annually. Researchers examined bariatric surgery discharge abstracts from 228,136 patients undergoing bariatric surgery in 429 inpatient hospitals in 8 states and compared the proportion of minority patients undergoing bariatric surgery with and without Medicare before and after implementation of the policy change. Non-Medicare patients were used as a control group to isolate associations with the Medicare policy change relative to trends among all bariatric surgeries over the study period. In addition, researchers compared the number of white patients with those from all other minority groups.

Earlier studies documenting better surgical outcomes at hospitals with higher procedure volume have prompted proposals to concentrate elective surgery in high-volume settings; these policies have been little-used in practice. To date, bariatric surgery is the only procedure for which the Centers for Medicare and Medicaid Services (CMS) have experimented with restrictions to high-volume hospitals. CMS recently proposed eliminating the centers of excellence requirement after studies suggested little if any safety benefit to bariatric centers of excellence and is expected to issue a decision later this month.

"Policies restricting patients to centers of excellence could lead to serious issues including, reducing access for vulnerable populations," suggest the authors.

"Morbidity and mortality associated with bariatric surgery have declined in recent years and safety gains from limiting hospital choice are likely lower than they were when the national coverage decision was implemented in 2006," adds Nicholas. "Our findings are important for bariatric surgery and also serve as a cautionary tale about the potential for unintended consequences if selective referral policies are extended to other procedures."