Changes in Bariatric Surgery Procedure Use in Michigan, 2006-2013

Bariatric surgery is the most effective therapy available for significant and sustainable weight loss in patients with morbid obesity.^1,2 As a result of the increasing prevalence of obesity, improvements in perioperative safety, and expanded insurance coverage, bariatric surgery use has increased during the last decade.^3,4

Changes in procedure use over time reflect emerging evidence regarding the comparative safety and effectiveness of available procedures.^1,2,5 An understanding of current trends in bariatric procedure use can inform primary care physicians counseling patients with morbid obesity who are considering surgical intervention.

Although recent reports have documented an increased use of sleeve gastrectomy (SG) in certain populations,^4,6 the extent to which this procedure has supplanted other procedures, such as Roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric banding (LAGB), is poorly understood. Moreover, it is unclear if relative use differs within clinical subgroups that might be predicted to have better outcomes with a specific procedure. To better understand current trends in bariatric surgery use, we examined procedure rates in patients undergoing bariatric surgery in Michigan between June 2006 and December 2013.

We studied adults undergoing primary inpatient and outpatient bariatric surgery within the 39-hospital Michigan Bariatric Surgery Collaborative between June 2006 and December 2013. Details of prospective data collection have been previously described.⁵

In brief, trained data abstractors review the medical record and collect information on patient demographics, comorbidities, intraoperative and perioperative processes, and 30-day outcomes of all patients undergoing bariatric surgery in participating hospitals. The hospitals are audited annually to ensure data accuracy. There are no missing data. This study was considered exempt by the institutional review board at the University of Michigan.

We calculated relative use stratified by procedure type and year of procedure, and we examined procedure rates within clinically important subgroups. The Cuzick test for trend was used to assess differences in procedure use across years, and the χ² test was used to evaluate differences in procedure use between subgroups. All P values are 2-tailed with α set at .05. Statistical analyses were performed using Stata version 12.1 (StataCorp).

The final cohort included 43 732 patients undergoing bariatric surgery. As shown in the Figure, relative use of SG increased from 6.0% (95% CI, 5.4%-6.6%) of all procedures in 2008 to 67.3% (95% CI, 66.0%-68.6%) of all procedures in 2013, which is an increase of 61%. During the same period, use of RYGB decreased from 58.0% (95% CI, 56.8%-59.1%) to 27.4% (95% CI, 26.2%-28.6%), and use of LAGB decreased from 34.5% (95% CI, 33.3%-35.6%) to 4.6% (95% CI, 4.1%-5.2%).

Changes in surgery use over time within clinically important subgroups (Table) were similar to the overall trend. Use of SG increased, whereas rates of RYGB and LAGB decreased. Even though SG was the most common procedure across all subgroups in 2012 and 2013, SG rates were relatively lower in patients aged 65 years or older (43.0% [95% CI, 39.4%-46.6%] vs 57.9% [95% CI, 56.9%-58.9%] in patients <65 years; P < .001), in patients with gastroesophageal reflux disease (53.2% [95% CI, 51.9%-54.5%] vs 60.8% [95% CI, 59.4%-62.1%] without reflux; P < .001), and in patients with type 2 diabetes (49.9% [95% CI, 48.3%-51.6%] vs 60.4% [95% CI, 59.3%-61.5%] without diabetes; P < .001).

Analysis of recent practice in Michigan revealed SG to be the most common procedure performed for patients pursuing bariatric surgery, surpassing RYGB in 2012. Moreover, despite controversy regarding the optimal procedure for patients with gastroesophageal reflux disease and type 2 diabetes,¹ SG has become the predominant procedure in both groups.

This analysis is limited to procedures performed in a single state. Although use of this detailed bariatric-specific registry in Michigan allows for a more accurate assessment of trends in procedure use than administrative data, it may limit the generalizability of our results. Although unmeasured confounders may influence procedure use, this bias is unlikely to alter these findings given the large magnitude of the differences observed.

Although long-term outcomes of SG are still unclear, these changes may reflect the favorable perioperative safety profile and emerging evidence of successful weight loss at 2 to 3 years after SG.⁵ These findings are important to inform primary care physicians of the predominant bariatric procedure currently used, regardless of preexisting comorbidity, and may assist in the preoperative counseling of patients considering surgical therapy for morbid obesity.

Corresponding Author: Bradley N. Reames, MD, MS, Center for Healthcare Outcomes and Policy, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI 48109 (breames@umich.edu).

Author Contributions: Dr Reames had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Finks, Bacal, Dimick.

Acquisition, analysis, or interpretation of data: Reames, Carlin.

Drafting of the manuscript: Reames, Bacal, Dimick.

Critical revision of the manuscript for important intellectual content: Reames, Finks, Carlin, Dimick.

Statistical analysis: Reames.

Administrative, technical, or material support: Bacal.

Study supervision: Finks, Bacal, Carlin, Dimick.

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Dimick reported serving as consultant and having an equity interest in ArborMetrix Inc, which provides software and analytics for measuring hospital quality and efficiency; however, the company had no role in the study. No other disclosures were reported.

Funding/Support: Dr Reames is supported by grant 5T32CA009672-23 from the National Cancer Institute.

Role of the Sponsor: The National Cancer Institute had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The views expressed in this article do not necessarily represent those of the US government.