Trends in procedure type, patient characteristics, and outcomes among persons with knee osteoarthritis undergoing bariatric surgery, 2005-2014.

OBJECTIVE: To evaluate trends in the utilization, clinical characteristics, and inpatient outcomes among persons with knee osteoarthritis undergoing bariatric surgery. METHOD: We used the National Inpatient Sample (NIS) to examine trends of bariatric surgeries performed on adults with clinically documented knee osteoarthritis between 2005 and 2014. We abstracted hospital setting, procedure, demographic and clinical characteristics, and inpatient surgical outcomes from each discharge. We examined temporal trends using linear regression and Cochran-Armitage test for trend. RESULTS: The utilization of bariatric surgery among persons with knee osteoarthritis from 2005 to 2014 remained consistent, with an annual total of about 3,300 procedures performed nationally. The most common procedure type changed from laparoscopic Roux-en-Y (65%) in 2005-2006 to laparoscopic sleeve gastrectomy (58%) in 2013-2014. The median age, proportion on Medicare, and age- and sex-adjusted prevalence of diabetes increased from 46 to 51 years, 7-23%, and 28-32%, respectively. From 2005 to 2014, the median adjusted costs, in 2017 USD, for laparoscopic and open Roux-en-Y surgeries decreased from $15,100 to $13,300 (p < 0.01) and $14,100 to $10,100 (p = 0.0001), respectively, whereas the costs of laparoscopic sleeve gastrectomy and laparoscopic banding did not change significantly. In-hospital mortality remained at 0.0-0.1% from 2005 to 2014. CONCLUSION: Although growing evidence suggests that bariatric surgery is associated with improvements in osteoarthritis pain and functional status, the utilization of bariatric surgery among morbidly obese persons with knee osteoarthritis remained consistent from 2005 to 2014. Bariatric surgery in persons with knee osteoarthritis is generally safe, as inpatient complication and mortality rates remained low despite an increase in age and number of comorbidities.