Weight Loss Surgery and Kids Part 2

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This series is part of the work I did with WIND (Weight Inclusive Nutrition and Dietetics) to create a comprehensive response to the disastrous American Academy of Pediatrics (AAP) guidelines for higher-weight children. I was part of the team that analyzed the research that, the AAP claims, supports their recommendations, and I’ll be publishing my breakdowns here as well.

You can find the other studies here:
Part 1
Part 3
Part 4

Today’s study is The effectiveness and risks of bariatric surgery: an updated systematic review and meta-analysis, 2003-2012 by Chang S-H, Stoll CRT, Song J, Varela JE, Eagon CJ, Colditz GA

Conflicts of interest/author issues

The authors claim no conflicts of interest

Dr. Chang – the lead author is an economist whose focus is on “health and economic consequences of ob*sity and surgical treatments of ob*sity.” This is concerning because the idea that if higher-weight people cost “too much” then it’s worth risking our lives/quality of life to make us thin is a eugenics-based argument, and using research to back that up doesn’t make it better, including and especially for recommendations that are meant for children.

J Esteban Varela and Christopher Eagon are bariatric surgeons who stand to benefit financially from the recommendations of this study

Quick Overview

In addition to issues with analysis and study quality, this study looks at a population with a mean age of 45, not pediatric populations and is thus not applicable to the populations discussed in the AAP guidelines, but I’m going to go ahead and analyze it.

The heterogeneity of the studies brings their choice of meta-analysis into question, and I’m concerned that their claim of “meta-analysis” may lead people to believe that the study conclusions are stronger than they actually are.

The short follow-up (43% of the studies included had less than 2 years of follow-up and the maximum follow-up was 5 years) is inadequate to judge the long-term consequences of a surgery that creates lifelong forced food restriction and, in some cases, malabsorption.

TLDR: There is absolutely nothing about this study that supports the idea that these surgeries are a good idea for anyone, let alone children as young as 13.

Introduction

Treatments of ob*sity, except surgery, are generally ineffective in long-term weight control 15-20

Note that while the AAP guideline’s authors cite this study to support their surgery recommendations, the study actually contravenes the guideline’s recommendations on Intensive Health Behaviors Lifestyle Treatments and pharmacotherapy.

In addition to sustained weight loss, surgical treatment provides additional benefits to people with ob*sity-related comorbidities and reduces relative risk of death due to significant weight loss.20–24

Let’s look at the citations they use to try to support their statement:

20 – Study (Cost-effectiveness of bariatric surgery: Should it be universally available?, 2011) by three of the same authors as this study. It attempts to make the case that surgery should be available to “all ob*se people” based on the rationale that it is “cost effective.” The majority of the studies they used to calculate this had less than 2 years of follow-up, and they used a series of assumptions and probabilities in lieu of actual long-term data. It does not support the statement above and does not specifically include pediatric patients.

21 – Study (Surgery decreases long-term mortality, morbidity, and health care use in morbidly ob*se patients, 2004) This study only looked at adult subjects for five years, which is insufficient follow-up to support their conclusions (or their title, as far as I’m concerned.)

22 – Study (Bariatric surgery reduces mortality in Swedish men) The entire study population is Swedish cisgender adult men. This study has issues with “matching” and other statistics, but I didn’t fully analyze it since the population has nothing to do with the American Academy of Pediatrics’ guidelines population.

23 – Study (Bariatric surgery: an overview of ob*sity surgery, 2007). Again, focuses on adult populations

24 – Study (Effects of Bariatric Surgery on Glucose Homeostasis and Type 2 Diabetes, 2012) Looks at the impact of weight loss surgeries on adult populations. There are significant limitations in terms of length of follow-up, and they gloss over significant, unexplained disease recurrence.

Specifically, we report the risks (defined as peri- and post-operative mortality, complications, and reoperations) and the effectiveness (defined as weight loss and remission of ob*sity-related diseases).

Here I want to point out that “ob*sity -related diseases” are diseases that people of all sizes get, that get called “ob*sity-related” when higher-weight people have them.

Note that their criteria ignores a significant number of adverse events and negative psychological impacts. Also, included studies needed only to report one outcome to be included.

They mention that 259 studies met the inclusion criteria, but they only included 164 studies, and only 37 of those were randomized controlled trials, the rest were observational studies.

The mean age was 45 so this is also not applicable to pediatric populations

Statistical Analysis

“Surgical complications included all adverse events associated with surgery reported in the studies, such as bleeding, stomal stenosis, leak, vomiting, reflux, gastrointestinal symptoms, and nutritional and electrolyte abnormalities”

The trick here is in the phrase “reported in the studies.” As we’ve seen many of these studies are authored/funded by people with significant personal and financial buy-in to the concept of these surgeries. When they get to choose which of the massive number of possible adverse events to include, they often choose to consider few events, and only for a short period of time. This is far from a complete list of complications and ignores other adverse events and psychological impacts including those that are truly long-term.

Also note that their use of Frequentist and Bayesian statistics relies heavily on probabilities.

Results

Again, their inclusion criteria only required one of the outcomes to be reported. So, for example, all 164 included studies reported weight change in some manner, but only 63 offered a mortality analysis during the first 30 days post-op. Only 47 offered a mortality analysis after 30 days, only 54 included a complications analysis and only 37 included a re-operation analysis. So, when they say in their conclusion that “Death rates were lower than those reported in previous meta-analyses” they should probably point out that only about 38% of the included studies actually offered a mortality analysis during the first 30 days post-op and only 29% included a mortality analysis after 30 days.

73 of the studies included had follow-up of less than 2 years. 91 had follow-up of greater than or equal to two years. The chart they provide shows 5 years as the longest follow-up with massive loss of subjects between years and all surgeries except gastric banding showing weight regain from years 4 through 5. This is, of course, not long enough to capture the long-term effects of surgeries that force food restriction and, in some cases, malabsorption, as well as dumping syndrome and other side effects.

They say that “Having loss to follow up >20% was associated with more significant weight loss in the second year after surgery.” This suggests that those who weren’t having significant weight loss may have dropped out of the study, creating an illusion of greater average weight loss.

To reiterate, there is absolutely nothing about this study that supports the idea that these surgeries are a good idea for anyone, let alone children as young as 13.

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More research and resources:
https://haeshealthsheets.com/resources/

*Note on language: I use “fat” as a neutral descriptor as used by the fat activist community, I use “ob*se” and “overw*ight” to acknowledge that these are terms that were created to medicalize and pathologize fat bodies, with roots in racism and specifically anti-Blackness. Please read Sabrina Strings Fearing the Black Body – the Racial Origins of Fat Phobia and Da’Shaun Harrison Belly of the Beast: The Politics of Anti-Fatness as Anti-Blackness for more on this.