Reporting of weight loss outcomes in bariatric surgery following introduction of 2015 ASMBS guidelines


  • 1.

    Heterogeneity in reporting weight loss outcomes has reduced though remains high.

  • 2.

    Timing of preoperative weight measurement is variable and not routinely specified.

  • 3.

    Most journals do not provide author instructions on reporting weight loss outcomes.



Heterogeneity in reporting weight loss (WL) outcomes within the bariatric surgery literature limits synthesis and meta-analysis. In 2015, the American Society for Metabolic and Bariatric Surgery (ASMBS) published reporting guidelines to achieve consistency in the literature.


We aimed to assess the effect of the ASMBS guidelines in the bariatric surgery literature.


Nine PubMed-indexed bariatric surgery journals were screened for articles published in the first 6 months of 2015 and 2021. Of 1807 articles, 105 and 158 articles in 2015 and 2021, respectively, reported primarily on WL outcomes following surgery.


Overall ASMBS compliance increased from 5% to 20%, P < .05. Initial weight and body mass index (BMI) was reported in all studies, but specification of this as the immediate preoperative weight reduced from 15% to 6%, P < .05. The percent total WL (%TWL) increased from 17% to 61%, P < .05. Change in the BMI (DBMI) remained 41%. The percent excess BMI or WL (%EBMIL or %EWL) did not significantly change from 76% to 69%, P = .203. In 2021, 2 of the 9 journals gave guidance on reporting WL in their instructions to authors. Thirty percent (42/142) of articles did not comply with the journals’ WL reporting guidance. The number of unique WL outcomes used increased from 45 to 54.


Significant heterogeneity in reporting WL outcomes remains, hindering robust meta-analysis of articles. Use of referral weight instead of preoperative weight can inflate WL in those with mandated preoperative WL, clarifying initial weight is needed. Use of nonstandard measures of WL remains high.


Prevalence of obesity continues to grow worldwide, leading to physical, mental, and financial consequences. According to the World Health Organization, there are 1.9 billion people across the world living with obesity [

Obesity and overweight.