Bariatric surgery and weight loss in the short- and long-term: Evidence from NHANES 2015-2018.

The present study aimed to examine short- and long-term weight change in a nationally representative sample of US adults who reportedly underwent bariatric surgery. Individuals aged 20-64 at survey from the US National Health and Nutrition Examination Survey 2015-2018 were included in the analyses (n = 6776). The primary comparison groups include 62 participants who underwent bariatric surgery, 1531 eligible but did not receive surgery, and 5183 not eligible for bariatric surgery. After adjusting for demographic characteristics and comorbidity, adults who reported receiving bariatric surgery were 5.0 times (4.0-6.0) more likely to achieve at least 20% weight loss from maximum weight relative to those who were eligible but reported no surgery. The likelihood appeared to be higher when surgery was performed within 10 years (short-term, PR 5.5, 95% CI: 4.0, 7.0) relative to surgeries that were performed for 10 or more years (long-term, PR 3.6, 95% CI: 2.0, 5.3). In this nationally representative sample of US adults, respondents who received bariatric surgery achieved substantial and significant weight loss compared with those who were eligible and did not receive bariatric surgery. Weight loss appeared to be most apparent in the short term and persisted over the long term.