National trends in utilization and outcomes of bariatric surgery

Background: Because of the growing interest in surgery to treat morbid obesity, this study examined changes in the utilization and in-hospital outcomes of bariatric surgery in the United States over a 10-year period. Methods: Data were obtained from the Nationwide Inpatient Sample, the largest all-payer discharge database in the United States. International Classification of Disease (ICD-9) codes were used to identify all bariatric procedures performed for adults from 1990 to 2000. Population-based rates of surgery for each year were calculated by applying sampling weights and U.S. Census data. Secular trends in annual rates of surgery, changes in patient characteristics, and in-hospital mortality and complications were analyzed. Results: From 1990 to 2000, the national annual rate of bariatric surgery increased nearly six fold, from 2.4 to 14.1 per 100,000 adults (p = 0.001). There has been more than a ninefold increase in the use of gastric bypass procedures (1.4 to 13.1 per 100,000; p < 0.001). This represents an increase from 55% of all bariatric procedures in 1990 to 93% of such procedures in 2000 (p < 0.001). The rates of in-hospital mortality were low (0.4% overall), but increased slightly over time (0.2% in 1990 to 0.5% in 2000; p = 0.009). There is no significant difference in adjusted mortality for the past 8 years, but a slight rise did occur over the full 10-year period. The rates for reoperation (1.3%) and pulmonary emboli (0.3%) remained stable. The rates for respiratory failure associated with bariatric surgery declined from 7.7% in 1990 to 4.5% in 2000 (p < 0.001). Over this time, the mean length of hospital stay declined from 6.0 to 4.1 days (p < 0.001). Conclusions: The annual rate of bariatric surgery in the United States increased nearly six fold between 1990 and 2000, with little change in in-hospital morbidity and mortality. This appears to be driven largely by the increasing popularity of gastric bypass procedures.