3-Month Post-Operative Increase in FGF21 is Predictive of One-Year Weight Loss After Bariatric Surgery

The association between bariatric surgery outcome and blood levels of fibroblast growth factor 21 (FGF21) remains controversial. Many patients displayed stable or decreased FGF21 one year after bariatric surgery. Nevertheless, there is often an early increase FGF21 concentration in the post-surgery period. The aim of this study was to investigate the relationship between 3-month FGF21 response and percentage total weight loss at one year after bariatric surgery.

In this prospective monocentric study, a total of 144 patients with obesity grade 2-3 were included; 61% of them underwent a sleeve gastrectomy and 39% a Roux-en-Y gastric bypass. Data analysis was carried out to determine the relation between 3-month plasma FGF21 response and weight loss one year after bariatric surgery. Multiple adjustments were done including degree of weight loss after 3 months.

FGF21 significantly increased between baseline and Month 3 (n = 144, p < 10^-3), then decreased between Month 3 and Month 6 (n = 142, p = 0.047) and was not different from baseline at Month 12 (n = 142, p = 0.86). The 3-month-FGF21 response adjusted to body weight loss was not different between types of bariatric surgery. The 3-month-FGF21 response was associated to body weight loss at Month 6 (r = -0.19, p = 0.02) and Month 12 (r = -0.34, p < 10^-4). After multiple regression analysis, only Month 12 body weight loss remained associated to 3-month FGF21 response (r = -0.3, p = 0.02).

This study showed that the magnitude of changes in FGF21 at 3 months after bariatric surgery emerged as an independent predictor of one-year body weight loss irrespective of the type of surgery.