Gastric Bypass Surgery among Veterans Not Associated with Reduced Healthcare Expenditures Three Years Later

BACKGROUND:
Obesity is difficult to treat, and bariatric surgery is the most effective means to induce weight loss for the severely obese, whose prevalence increased by 50% from 2000 to 2005. As the demand for bariatric surgery has increased, numbers of non-white, older, and male patients with a greater prevalence of obesity-related comorbidities undergoing bariatric surgery have increased, and their expenditure trends have not been evaluated extensively. Therefore, the purpose of this retrospective cohort study was to determine whether bariatric surgery is associated with reduced healthcare expenditures in a multi-site cohort of predominantly older male Veterans with a substantial disease burden. Investigators identified 847 Veterans who'd had gastric bypass surgery in one of 12 VAMCs from 2000 to 2006; they were matched to 847 Veterans from the same VAMCs who had not had the procedure. Bariatric patients were identified from a database of major surgical procedures performed in VAMCs and maintained by the VA Surgical Quality Improvement Program (VASQIP). Investigators then examined outpatient, inpatient, and total VA expenditures, comparing differences in healthcare costs between Veterans who had undergone bariatric surgery and those who had not undergone the procedure. VA costs were examined for three years prior to surgery and three years after.

FINDINGS:

• Gastric bypass surgery does not appear to be associated with reduced healthcare expenditures three years after the procedure.
• Total expenditures trended higher for bariatric surgical cases in the year leading up to the procedure and then converged back to the lower expenditure levels of non-surgical controls one year after the procedure.
• Health expenditures were similar two and three years before the surgical procedure because surgical patients and non-surgical controls had similar weight and healthcare use trajectories several years before giving serious consideration to bariatric surgery.
• These results are notable because they contrast with results from several prior observational studies that found costs among post-surgical cases to be lower than those of non-surgical controls two to four years after the procedures. This may be explained by important differences in the populations examined (e.g., Veterans are generally older and sicker than the general population) and the methods of analysis.

LIMITATIONS:

• These results do not account for unobserved cofounding that may persist even after propensity score matching because the analysis was based on a quasi-experimental design from administrative data rather than from a randomized trial.

AUTHOR/FUNDING INFORMATION:
This study was funded by HSR&D (IIR 05-201; SHP 08-137). Dr. Maciejewski also is supported by an HSR&D Research Career Scientist Award. Dr. Maciejewski and Ms. Smith are part of HSR&D's Center for Health Services Research in Primary Care, Durham, NC. The authors would like to acknowledge the VA Surgical Quality Data Use Group (SQDUG) for its role as scientific advisors and for the critical review of data use and analysis presented in this manuscript.

Maciejewski ML, Livingston E, Smith V, Kahwati L, Henderson W, and Arterburn D. Health Expenditures among High-Risk Patients after Gastric Bypass and Matched Controls. Archives of Surgery July 2012;147(7):633-640.