An analysis of the impact of surgical volume and diffusion on bariatric surgery outcomes

Statement of Problem/Objectives: Obesity has become a major national public health concern as the percentage of Americans who are overweight and obese has increased at an alarming rate over the past 15 years. With increasing evidence of its effectiveness in weight loss and health improvement, the use of bariatric surgery increased more than nine-fold from 1998 to 2004. Although several studies have been published on outcomes of bariatric surgery, current information is limited regarding the impact of individual surgeon or facility volume variation on complications, length of stay (LOS), and cost outcomes, particularly since the introduction of laparoscopic adjustable gastric banding (LAGB). The specific impact of the introduction of laparoscopic approaches to bariatric surgery, especially LAGB, on the rapid diffusion of bariatric surgery has not been adequately evaluated and may impact the clinical outcome, cost, and rate of growth of bariatric surgery.;Methods: The first research question addressed the effect of volume variation by individual surgeon and hospital on the complications, cost, and LOS associated with bariatric surgery. Outcomes were adjusted for the effect of bariatric surgery type, patient age, and patient gender. Robust regression modeling approaches were used for the analysis, and clustering between surgeon and facility was considered. The second research question addressed the longitudinal pattern of diffusion of total bariatric surgery and open bypass, laparoscopic bypass, and LAGB approaches in the context of classical diffusion theory, and its effect on LOS, surgeon and facility payment, and complication outcomes.;Results: The adoption and diffusion of bariatric surgery and the type of bariatric surgery changed markedly over the period of 2002 to 2008. After a dramatic increase in bariatric surgery in the decade preceding and including the first two years of this study, overall bariatric surgery plateaued in BCBSm, consistent with nationwide volumes. However, marked changes occurred in the diffusion of bariatric surgery by type, influenced by factors consistent with classical diffusion of innovation. Open gastric bypass surgery, which was performed almost exclusively in 2002, began to decline sharply as laparoscopic gastric bypass came into favor in 2004. With the rapid growth in LAGB, by 2008 open gastric bypass cases declined to less than 4% of open cases done in 2002 and laparoscopic bypass began to plateau. New surgeons who perform only LAGB entered the market beginning in 2005, and LAGB continued on a steep upward phase of diffusion. These changes led to reductions in LOS, cost, and complications. Potential factors influencing the diffusion patterns of bariatric surgery over this time period are assessed in the context of classical theory on diffusion of innovations.;Conclusions: Higher surgeon and higher facility volume each reduced the number of serious complications after bariatric surgery. The perioperative infection nature of many of these volume-related complications suggests the potential for prevention through current and planned changes in reimbursement policy based on quality outcomes. Increased volume also shortened LOS and reduced costs. Facility effects influenced differences in payment to both surgeon and facility and could reflect regional differences in contracts and reimbursement. Patterns in changes in frequency of bariatric surgery by type over the period of 2002 to 2008 and the reasons for such changes provide comprehensive evidence that classical theories of diffusion of innovation are highly relevant to bariatric surgery. The rapid displacement of gastric bypass by LAGB may have negative implications for health outcomes and surgical efficacy in obesity. LAGB results in markedly less weight loss than bypass approaches, may have a limited duration of weight loss in some patients, and has been recently recognized to have a high longterm rate of failure and reoperation Thus the overall health benefit associated with bariatric surgery could decrease if current diffusion curves continue. These findings can strongly inform policy in regard to appropriate incentives to reduce complications and in providing caution and guidance in determining the appropriate approach to bariatric surgery. (Abstract shortened by UMI.).