The FAT Score, a Fibrosis Score of Adipose Tissue: Predicting Weight-Loss Outcome After Gastric Bypass

J Clin Endocrinol Metab. 2017 Jul 1;102(7):2443-2453. doi: 10.1210/jc.2017-00138.


Context: Bariatric surgery (BS) induces major and sustainable weight loss in many patients. Factors predicting poor weight-loss response (PR) need to be identified to improve patient care. Quantification of subcutaneous adipose tissue (scAT) fibrosis is negatively associated with post-BS weight loss, but whether it could constitute a predictor applicable in clinical routine remains to be demonstrated.

Objective: To create a semiquantitative score evaluating scAT fibrosis and test its predictive value on weight-loss response after Roux-en-Y gastric bypass (RYGB).

Methods: We created a fibrosis score of adipose tissue (FAT score) integrating perilobular and pericellular fibrosis. Using this score, we characterized 183 perioperative scAT biopsy specimens from severely obese patients who underwent RYGB (n = 85 from a training cohort; n = 98 from a confirmation cohort). PR to RYGB was defined as <28% of total weight loss at 1 year (lowest tertile). The link between FAT score and PR was tested in univariate and multivariate models.

Results: FAT score was directly associated with increasing scAT fibrosis measured by a standard quantification method (P for trend <0.001). FAT score interobserver agreement was good (κ = 0.76). FAT score ≥2 was significantly associated with PR. The association remained significant after adjustment for age, diabetes status, hypertension, percent fat mass, and interleukin-6 level (adjusted odds ratio, 3.6; 95% confidence interval, 1.8 to 7.2; P = 0.003).

Conclusion: The FAT score is a new, simple, semiquantitative evaluation of human scAT fibrosis that may help identify patients with a potential limited weight-loss response to RYGB.

Trial registration: NCT01655017.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / metabolism
  • Adipose Tissue / pathology*
  • Adult
  • Body Mass Index*
  • Cohort Studies
  • Confidence Intervals
  • Female
  • Fibrosis / pathology
  • Gastric Bypass / methods*
  • Humans
  • Male
  • Middle Aged
  • Obesity, Morbid / metabolism
  • Obesity, Morbid / surgery*
  • Odds Ratio
  • Predictive Value of Tests
  • Reproducibility of Results
  • Retrospective Studies
  • Weight Loss / physiology*

Associated data