Data are collected on patient characteristics, comorbidities, and outcomes, with further information obtained from annual
surveys. For this study, the researchers identified 25,469 patients undergoing a primary (nonrevisional) bariatric surgery
procedure between June 2006 and December 2010. Baseline and follow-up surveys at one, two, and three years were completed
by 66 percent, 31 percent, 22 percent, and 12 percent, respectively.