Risk of mortality following bariatric surgery
Nutrition Research Newsletter, Nov, 2005
The majority of adults in the United States are overweight or obese. Obesity may soon become the leading cause of death in this country. Bariatric surgical procedures are the only interventions that consistently achieve significant and sustained weight loss and improvements in the comorbid medical conditions associated with obesity. There has been a dramatic growth in bariatric surgery over the last decade. While the benefits of the surgery can be vast, they are balanced against the risks of perioperative death and short-term adverse outcomes. Unfortunately, these risks have been poorly defined in the general population.
Medicare, the United States' largest healthcare insurer, currently reimburses for bariatric procedures on a region basis and is the primary payer for approximately 20% of all procedures performed in at least one state. However, Medicare policy in this area is currently at a crossroads: there is no national coverage decision and no consensus regarding the efficacy and safety of bariatric surgery in older patients. Investigators performed a study to determine the risk of all-cause early postsurgical mortality among Medicare beneficiaries undergoing open bariatric surgery to help inform patients, clinicians, insurers, and other stakeholders who are involved in medical decision making. A secondary goal of the research was to determine the risk of adverse outcomes among older Medicare beneficiaries undergoing these procedures compared with that of younger patients.
A retrospective cohort design, using Medicare National Claims History Part B data from January 1, 1996, through December 31, 2002, was used. The Medicare Part B database, maintained by the Centers for Medicare and Medicaid Services (CMS), contains all the payment claims for the professional component of services delivered to Medicare beneficiaries in either an inpatient or an outpatient setting. Dates of death were obtained from the Enrollment Database, which is obtainable from the Social Security Administration's database.
Subjects were defined as having had bariatric surgery if they had a claim for any of the following procedures: 1) CPT code 43842: gastric restrictive procedure without gastric bypass for morbid obesity; vertical-banded gastroplasty; 2) CPT code 43843: gastric bypass for morbid obesity; other than vertical-banded gastroplasty; 3) CPT code 43846: gastric restrictive procedure with gastric bypass for morbid obesity, with short-limbed (<100 cm) Roux-en-Y gastroenterostomy (RYGB); 4) CPT code 43848: gastric restrictive procedure with gastric bypass for morbid obesity with small intestine reconstruction to limit absorption (including long limbed [>100 cm] gastric bypass and distal bypasses such as biliopancreatic diversion); or 5) CPT code 43848: revision of gastric restrictive procedure for morbid obesity.
The total number of claims for bariatric procedures for each surgeon was calculated. To adjust for potential confounding based on comorbid conditions, a modified Charlson Comorbidity Index was calculated for each patient based on available claims. The date of all-cause death was obtained and reported at 30 days, 90 days and 1 year after bariatric procedures.
There were a total of 16,155 patients who underwent bariatric procedures. The rates of 30-day, 90-day, and 1-year mortality were 2.0%, 2.8%, and 4.6% respectively. Men had higher rates of early death than women. Mortality rates were greater for those aged 65 years or older compared with younger patients (4,8% vs 1.7% at 30 days, 6.9% vs 2.3% at 90 days, and 11.1% vs 3.9% at 1 year; P <.001). After adjustment for sex and comorbidity index, the odds of death within 90 days were five-fold greater for older Medicare beneficiaries (aged e" 75 years; n=136) than for those aged 65 yrs to 74 yrs (n=1381; odds ratio, 5.0; 95% confidence interval, 3.1-8.0). The odds of death at 90 days were 1.6 times higher (95% confidence interval, 1.3-2.0) for patients of surgeons with less than the median surgical volume of bariatric procedures (among Medicare beneficiaries during the study period) after adjusting for age, sex, and comorbidity index.
Among Medicare beneficiaries, the risk of early death following bariatric surgery is much higher than previously thought. Advancing age, being male, and the number of procedures the surgeon has performed were all associated with an increase in mortality.
D. Flum, L. Salem J. Elrod, et al. Early mortality among Medicare beneficiaries undergoing bariatric surgical procedures. JAMA; 294:1903-1908 (October 19, 2005) [Correspondence: David R. Flum, MD, MPH, Department of Surgery, University of Washington, Box 356410, 1959 NE Pacific St, Seattle, WA 98195-7183. E-mail:
daveflum@u.washington.edu]
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