Obesity in adolescents
Myron Yaster MD, Paul Samuels MD, and Michale Ok MD
A little over a decade ago, Dr. Paul Samuels of the Children’s Hospital of Cincinnati gave one of the most consequential lectures ever presented at a SPA meeting. His lecture on childhood obesity and the anesthetic management of adolescent bariatric surgery profoundly affected me and many other attendees, not only in how we think about the perioperative care of obese pediatric patients, but also how we personally manage our own diets and weight. His argument introduced the idea that obesity is more than the result of overeating – that there are significant underlying biologic and genetic phenomena that predispose an individual to obesity. He presented data on how unlikely it was that an obese adolescent would go on to become a normal weight adult. He then went on to describe the long-term risk of pediatric obesity including the resulting burden of chronic disease and premature death, providing an impetus for the aggressive treatment of pediatric obesity, including the use of bariatric surgery in this patient population.
Indeed, the legacy of that lecture persists to this day. Prior to his lecture, the food served at our national meeting was typically a sweet, sugary fare with hardly a protein or vegetable in sight. Ever since, healthier choices have become the standard.
When I saw today’s PAAD by Hannon et al.1 in the New England Journal of Medicine, I knew I had to ask Paul to help. We chatted about how the management of childhood obesity has continued to evolve over the past decade. Sadly, the prevalence of pediatric obesity in the US has continued to rise, which may in part explain the greater acceptance and availability of adolescent bariatric surgery. However, new and exciting pharmacologic options are emerging that may offer new treatment options for individuals who struggle with their weight. The practical importance of this content could not be clearer as healthcare providers continue to address one of our most common and vexing clinical challenges of our time. Indeed, obesity is to this generation what smoking was to mine. Myron Yaster MD
Review article
Hannon TS, Arslanian SA. Obesity in Adolescents. N Engl J Med. 2023 Jul 20;389(3):251-261. doi: 10.1056/NEJMcp2102062. PMID: 37467499
The review by Hannon et. al. presents a clinical vignette of a 12-year-old male with a history of significant obesity since the age of 6. He’s described as having a BMI of just under 42, which if we take the average 12-year-old boy translates to a 5-foot-tall weighing approximately 215 pounds. I would imagine that many of us see patients exactly like this on a weekly if not daily basis. This young man has developed numerous obesity-related co-morbidities including prediabetes, dyslipidemia and non-alcoholic liver disease. Hannon reviews the management of a case such as this, informed by the latest data on the successes (and failures) of contemporary obesity management. He describes obesity-related co-morbidities which also include polycystic ovary syndrome (PCOS), obstructive sleep apnea, mental health disorders and social stigma. Obesity during adolescence is also a strong risk factor for complications and death from coronary heart disease as well as for death from any cause in adulthood, including early adulthood.1 The prevalence of pediatric obesity has continued to increase and represents a significant international health care crisis with profound implications for future life expectancy and health care spending. In the United States, the prevalence of obesity in 2015-2016 was 20.6% among adolescents (as compared with 14.8% in the 1999–2000 period) — 22.0% among non-Hispanic Black adolescents and 25.8% among Hispanic adolescents. 1, 2 Pediatric obesity also disproportionately impacts low income communities and communities of color, groups that already have issues with access to healthcare. There are numerous social drivers of obesity including the marketing of unhealthy foods and drinks3, and cheap, readily available, high caloric fast foods.
The definitions for weight descriptors are different for adolescents than adults. In adults, a BMI between 25 to less than 30 is defined as overweight and a BMI above 30 is defined as obese. Recall that BMI in children is meaningless because a child’s BMI changes dramatically as a child grows. (A BMI of 19 in a 5 year old is high while the same BMI in a 17 year old is low) Instead, we look at BMI percentiles in children - a BMI at or above the 85th percentile but below the 95th percentile is diagnostic of overweight, and a BMI at or above the 95th percentile is diagnostic of obesity.4 The article provides a useful table (Table 2) which concisely summarizes the diagnostic laboratory criteria for common conditions that are associated with obesity in adolescents. As anesthesia providers, we may be the first to see a lab abnormality, physical finding, or vital sign indicative of a more significant co-morbidity. We should always be vigilant in this setting, cognizant that we may be in a position to bring a health concern to the attention of a parent and patient. Hannon uses strong language when describing nutritional recommendations, including the “elimination” of nutritionally empty high calorie beverages such as soft drinks and juices. We should also exercise some sensitivity when describing our patients as obese. Imagine how that feels on the receiving end.
For the purpose of this review, we will focus the remainder of our discussion on anti-obesity medications, bariatric surgery, and an issue that is not discussed in the article at all, namely perioperative anesthetic drug dosing.
Bariatric surgery, which include the Roux-en-Y gastric bypass and vertical sleeve gastrectomy, has been found to result in clinically relevant and sustained weight loss in adolescents. A 2018 study in the NEJM describes a 26% weight loss that was present 5 years after surgery. This weight loss in turn resulted in the remission of diabetes and hypertension greater than that seen in adults following similar surgery.5 While the Roux-en-Y remains the gold-standard procedure to which all other bariatric surgeries are compared, the risk of malabsorption and gastric dumping following the Roux has resulted in the sleeve now being the most commonly performed adolescent bariatric procedure.6 All children with obesity, regardless of their planned procedure, demand a thorough preoperative assessment to screen for other obesity-related comorbidities and potential airway problems. Evaluating for OSA, the use of home CPAP or BIPAP, and consideration of the most appropriate setting to have surgery (inpatient facility vs. ambulatory surgery center) is critical as these patients are more prone to difficulty with vascular access, mask ventilation, intraoperative desaturation, and postoperative airway obstruction.
The American Academy of Pediatrics recently revised their guidelines on childhood obesity adding anti-obesity medications to their armamentarium of weight loss strategies, which in the past focused on healthy behavior and lifestyle management.7 Until recently, only a handful of anti-obesity medications had been approved by the FDA in adolescents including orlistat (a lipase inhibitor), phentermine (an amphetamine analog), and phentermine-topiramate XR. More recently, there has been an explosion in interest in glucacon-like peptide 1 (GLP 1) receptor agonists such as liraglutide and semaglutide with the approval of this class of medications.
GLP-1 receptor agonists work by enhancing insulin secretion, delaying gastric emptying, reducing post prandial glucagon levels, and curbing appetite. Data supporting their efficacy in adults has been robust, including a NEJM article in 2021 describing a very successful trial in adults that resulted in a mean body weight loss of almost 15%.8 These medications have become very popular in adults, and the American Society of Anesthesiologists recently supported withholding them prior to surgery to minimize aspiration risk.9 When combined with lifestyle therapy, these drugs have produced dramatic weight loss equivalent to or better than lifestyle interventions alone in adolescents as well.10,11 One of these studies describes a mean weight loss of 16% over a 68 week period in adolescents. This dramatic weight loss has resulted in tremendous excitement as pediatric healthcare providers consider how to best use these novel pharmacologic tools.
We should note that the evidence for the use of these medications in adolescents are largely limited to observational studies and no long-term data is currently available. In addition, adult studies suggest that weight gain following the cessation of GLP-1 agonists is common.12 We should consider the possibility that GLP-1 agonists will become part of a long-term strategy for the maintenance of a healthy weight which in turn begs the question: what are the risks and benefits of a lifetime on GLP-1 agonists? How should these medications be best used either alone or in combination with other treatments modalities? Time and future research will tell.
Determining the appropriate weight-basd dosieng of medications when treating an obese patient is an almost daily challenge for anesthesia providers. This challenge is compounded by the complex and sometimes impractical dosing recommendations in the anesthesia literature. Available evidence suggests that midazolam and morphine should be dosed using ideal body weight while fentanyl, remifentanil, and cisatracurium should be dosed according to lean body weight.13 Propofol boluses should be dosed using lean body weight, whereas propofol infusions should be calculated utilizing total body weight in an allometric function with an exponent of 0.75.14,15 Succinylcholine and neostigmine should be dosed utilizing actual body weight. At our institution, when limited evidence-based guidance is available, lean body weight is used to dose most anesthetic medications. Lean body weight can be determined using numerous online tools. A quick and easy approximation of lean body weight can also be calculated by multiplying the child’s age in years by 4 for males or by 3.5 for females. The product of this calculation yields a number that falls between the 50th and 75th percentiles for any given age.
What do you do in your practice? Do you limit surgery to inpatient settings or can they be performed on an outpatient basis? How do you calculate drug dosing? Do you use or even know about allometric dosing? Send your thoughts to Myron who will post in a Friday reader response.
References
1. Hannon TS, Arslanian SA. Obesity in Adolescents. New England Journal of Medicine. 2023;389(3):251-261. doi:10.1056/NEJMcp2102062
2. Hales CM, Fryar CD, Carroll MD, Freedman DS, Ogden CL. Trends in Obesity and Severe Obesity Prevalence in US Youth and Adults by Sex and Age, 2007-2008 to 2015-2016. Jama. 2018;319(16):1723-1725. doi:10.1001/jama.2018.3060
3. Boyland EJ, Nolan S, Kelly B, et al. Advertising as a cue to consume: a systematic review and meta-analysis of the effects of acute exposure to unhealthy food and nonalcoholic beverage advertising on intake in children and adults12. The American Journal of Clinical Nutrition. 2016/02/01/ 2016;103(2):519-533. doi:https://doi.org/10.3945/ajcn.115.120022
4. Hampl SE, Hassink SG, Skinner AC, et al. Clinical Practice Guideline for the Evaluation and Treatment of Children and Adolescents With Obesity. Pediatrics. 2023;151(2)doi:10.1542/peds.2022-060640
5. Inge TH, Courcoulas AP, Jenkins TM, et al. Five-Year Outcomes of Gastric Bypass in Adolescents as Compared with Adults. The New England journal of medicine. May 30 2019;380(22):2136-2145. doi:10.1056/NEJMoa1813909
6. Hampl, S. E., Hassink, S. G., Skinner, A. C., Armstrong, S. C., Barlow, S. E., Bolling, C. F., ... & Okechukwu, K. (2023). Clinical practice guideline for the evaluation and treatment of children and adolescents with obesity. Pediatrics, 151(2), e2022060640.
7. Hampl, S. E., Hassink, S. G., Skinner, A. C., Armstrong, S. C., Barlow, S. E., Bolling, C. F., ... & Okechukwu, K. (2023). Clinical practice guideline for the evaluation and treatment of children and adolescents with obesity. Pediatrics, 151(2), e2022060640.
8. Wilding JPH, Batterham RL, Calanna S, Davies M, Van Gaal LF, Lingvay I, McGowan BM, Rosenstock J, Tran MTD, Wadden TA, Wharton S, Yokote K, Zeuthen N, Kushner RF; STEP 1 Study Group. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021 Mar 18;384(11):989-1002. doi: 10.1056/NEJMoa2032183. Epub 2021 Feb 10. PMID: 33567185.
9. American Society of Anesthesiologists. Patients Taking Popular Medications for Diabetes and Weight Loss Should Stop Before Elective Surgery, ASA Suggests. Accessed 07/20/2023, www.asahq.org/about-asa/newsroom/news-releases/2023/06/patients-taking-popular-medications-for-diabetes-and-weight-loss-should-stop-before-elective-surgery
10. Kelly AS, Auerbach P, Barrientos-Perez M, et al. A Randomized, Controlled Trial of Liraglutide for Adolescents with Obesity. The New England journal of medicine. May 28 2020;382(22):2117-2128. doi:10.1056/NEJMoa1916038
11. Weghuber D, Barrett T, Barrientos-Pérez M, et al. Once-Weekly Semaglutide in Adolescents with Obesity. The New England journal of medicine. Dec 15 2022;387(24):2245-2257. doi:10.1056/NEJMoa2208601
12. Wilding JPH, Batterham RL, Davies M, Van Gaal LF, Kandler K, Konakli K, Lingvay I, McGowan BM, Oral TK, Rosenstock J, Wadden TA, Wharton S, Yokote K, Kushner RF; STEP 1 Study Group. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes Obes Metab. 2022 Aug;24(8):1553-1564. doi: 10.1111/dom.14725. Epub 2022 May 19. PMID: 35441470; PMCID: PMC9542252.
13. Burke C.N., Voepel-Lewis T., Wagner D., Lau I., Baldock A., Malviya S, et. al.: A retrospective description of anesthetic medication dosing in overweight and obese children. Paediatric Anaesthesia 2014; 24: pp. 857-862.
14. Diepstraten J., Chidambaran V., Sadhasivam S., Esslinger H.R., Cox S.L., Inge T. H, et. Al.: Propofol clearance in morbidly obese children and adolescents. Clinical Pharmacokinetics 2012; 51: pp. 543-551.
15. Olutoye O.A., Yu X., Govindan K., Tjia I.M., East D.L., Spearman R, et. al.: The effect of obesity on the ED(95) of propofol for loss of consciousness in children and adolescents. Anesthesia and Analgesia 2012; 115: pp. 147-153.