AGP Report: Continuous Glucose Monitoring
8. Obesity and Weight
Management for the Prevention and Treatment of Type 2
Diabetes: Standards of Medical Care in Diabetes—2022
Diabetes Care 2022;45(Suppl. 1):S113–S124 | https://doi.org/10.2337/dc22-S008
American Diabetes Association Professional Practice Committee*
The American Diabetes Association (ADA) “Standards of Medical Care in Diabetes”
includes the ADA’s current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multi-disciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA’s clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.
There is strong and consistent evidence that obesity management can delay the pro-gression from prediabetes to type 2 diabetes (1–5) and is highly beneficial in the treat-ment of type 2 diabetes (6–17). In patients with type 2 diabetes and overweight or obesity, modest weight loss improves glycemic control and reduces the need for glu-cose-lowering medications (6–8), and more intensive dietary energy restriction can substantially reduce A1C and fasting glucose and promote sustained diabetes remission through at least 2 years (10,18–22). Metabolic surgery strongly improves glycemic con-trol and often leads to remission of diabetes, improved quality of life, improved cardio-vascular outcomes, and reduced mortality. The importance of addressing obesity is further heightened by numerous studies showing that both obesity and diabetes increase risk for more severe coronavirus disease 2019 (COVID-19) infections (23–26).
The goal of this section is to provide evidence-based recommendations for obesity management, including behavioral, pharmacologic, and surgical interventions, in patients with type 2 diabetes. This section focuses on obesity management in adults;
further discussion on obesity in older individuals and children can be found in Section 13,“Older Adults” (https://doi.org/10.2337/dc22-S013), and Section 14, “Children and Adolescents” (https://doi.org/10.2337/dc22-S014), respectively.
ASSESSMENT Recommendations
8.1 Use person-centered, nonjudgmental language that fosters collaboration between patients and providers, including people-first language (e.g.,
“person with obesity” rather than “obese person”).E
*A complete list of members of the American Diabetes Association Professional Practice Com-mittee can be found at https://doi.org/10.2337/
dc22-SPPC.
Suggested citation: American Diabetes Asso-ciation Professional Practice Committee. 8.
Obesity and weight management for the prevention and treatment of type 2 diabetes:
Standards of Medical Care in Diabetes—2022.
Diabetes Care 2022;45(Suppl. 1):S113–S124
© 2021 by the American Diabetes Association.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
More information is available at https://
diabetesjournals.org/journals/pages/license.
8.OBESITYANDWEIGHTMANAGEMENT
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8.2 Measure height and weight and calculate BMI at annual visits or more frequently. Assess weight trajectory to inform treatment considerations.E
8.3 Based on clinical considerations, such as the presence of comor-bid heart failure or significant unexplained weight gain or loss, weight may need to be moni-tored and evaluated more fre-quently. B If deterioration of medical status is associated with significant weight gain or loss, inpatient evaluation should be considered, especially focused on associations between medication use, food intake, and glycemic status.E
8.4 Accommodations should be made to provide privacy during weighing.E
A person-centered communication style that uses inclusive and nonjudgmental language and active listening, elicits patient preferences and beliefs, and assesses potential barriers to care should be used to optimize patient health out-comes and health-related quality of life.
Use people-first language (e.g., “person with obesity” rather than “obese per-son”) to avoid defining patients by their condition (27–29).
Height and weight should be mea-sured and used to calculate BMI annually or more frequently when appropriate (19). BMI, calculated as weight in kilo-grams divided by the square of height in meters (kg/m2), is calculated automati-cally by most electronic medical records.
Use BMI to document weight status (overweight: BMI 25–29.9 kg/m2; obesity class I: BMI 30–34.9 kg/m2; obesity class II: BMI 35–39.9 kg/m2; obesity class III:
BMI$40 kg/m2), but note that misclassi-fication can occur, particularly in very muscular or frail individuals. In some groups, notably Asian and Asian Ameri-can populations, the BMI cut points to define overweight and obesity are lower than in other populations due to differ-ences in body composition and cardio-metabolic risk (Table 8.1) (30,31). Clinical considerations, such as the presence of comorbid heart failure or unexplained weight change, may warrant more frequent
weight measurement and evaluation (32,33). If weighing is questioned or refused, the practitioner should be mind-ful of possible prior stigmatizing experi-ences and query for concerns, and the value of weight monitoring should be explained as a part of the medical evalu-ation process that helps to inform treat-ment decisions (34,35). Accommodations should be made to ensure privacy during weighing, particularly for those patients who report or exhibit a high level of weight-related distress or dissatisfaction.
Scales should be situated in a private area or room. Weight should be mea-sured and reported nonjudgmentally.
Care should be taken to regard a patient’s weight (and weight changes) and BMI as sensitive health information.
In addition to weight and BMI, assess-ment of weight distribution (including propensity for central/visceral adipose deposition) and weight gain pattern and trajectory can further inform risk stratification and treatment options (36).
Providers should advise patients with overweight or obesity and those with increasing weight trajectories that, in general, higher BMIs increase the risk of diabetes, cardiovascular disease, and all-cause mortality, as well as other adverse health and quality of life outcomes. Pro-viders should assess readiness to engage in behavioral changes for weight loss and jointly determine behavioral and weight loss goals and patient-appropri-ate intervention strpatient-appropri-ategies (37). Strpatient-appropri-ate- Strate-gies may include dietary changes, physical activity, behavioral counseling, pharmacologic therapy, medical devices, and metabolic surgery (Table 8.1). The latter three strategies may be considered for carefully selected patients as adjuncts to dietary changes, physical activity, and behavioral counseling.
DIET, PHYSICAL ACTIVITY, AND BEHAVIORAL THERAPY
Recommendations
8.5 Diet, physical activity, and behav-ioral therapy to achieve and maintain $5% weight loss is recommended for most people with type 2 diabetes and over-weight or obesity. Additional weight loss usually results in fur-ther improvements in control
of diabetes and cardiovascular risk.B
8.6 Such interventions should include a high frequency of counseling ($16 sessions in 6 months) and focus on dietary changes, physical activity, and behavioral strategies to achieve a 500–750 kcal/day energy deficit.A
8.7 An individual’s preferences, motivation, and life circum-stances should be considered, along with medical status, when weight loss interventions are recommended.C
8.8 Behavioral changes that create an energy deficit, regardless of macronutrient composition, will result in weight loss. Dietary recommendations should be individualized to the patient’s preferences and nutritional needs.A
8.9 Evaluate systemic, structural, and socioeconomic factors that may impact dietary pat-terns and food choices, such as food insecurity and hunger, access to healthful food options, cultural circumstances, and social determinants of health.C 8.10 For those who achieve weight
loss goals, long-term ($1 year) weight maintenance programs are recommended when avail-able. Such programs should, at minimum, provide monthly con-tact and support, recommend ongoing monitoring of body weight (weekly or more fre-quently) and other self-monitor-ing strategies, and encourage regular physical activity (200– 300 min/week).A
8.11 Short-term dietary intervention using structured, very-low-calo-rie diets (800–1,000 kcal/day) may be prescribed for carefully selected individuals by trained practitioners in medical set-tings with close monitoring.
Long-term, comprehensive wei-ght maintenance strategies and counseling should be integrated to maintain weight loss.B 8.12 There is no clear evidence
that dietary supplements are effective for weight loss.A
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Among patients with both type 2 diabe-tes and overweight or obesity who have inadequate glycemic, blood pressure, and lipid control and/or other obesity-related medical conditions, modest and sustained weight loss improves glycemic control, blood pressure, and lipids and may reduce the need for medications to control these risk factors (6–8,38).
Greater weight loss may produce even greater benefits (20,21). For a more detailed discussion of lifestyle manage-ment approaches and recommendations see Section 5, “Facilitating Behavior Change and Well-being to Improve Health Outcomes” (https://doi.org/
10.2337/dc22-S005). For a detailed dis-cussion of nutrition interventions, please also refer to “Nutrition Therapy for Adults With Diabetes or Prediabetes:
A Consensus Report” (39).
Look AHEAD Trial
Although the Action for Health in Diabe-tes (Look AHEAD) trial did not show that the intensive lifestyle intervention reduced cardiovascular events in adults with type 2 diabetes and overweight or obesity (40), it did confirm the feasibility of achieving and maintaining long-term weight loss in patients with type 2 diabe-tes. In the intensive lifestyle intervention group, mean weight loss was 4.7% at 8 years (41). Approximately 50% of inten-sive lifestyle intervention participants lost and maintained$5% of their initial body weight, and 27% lost and maintained
$10% of their initial body weight at 8 years (41). Participants assigned to the intensive lifestyle group required fewer glucose-, blood pressure–, and lipid-low-ering medications than those randomly assigned to standard care. Secondary analyses of the Look AHEAD trial and other large cardiovascular outcome stud-ies document additional benefits of weight loss in patients with type 2 diabe-tes, including improvements in mobility,
physical and sexual function, and health-related quality of life (32). Moreover, several subgroups had improved cardio-vascular outcomes, including those who achieved >10% weight loss (42) and those with moderately or poorly con-trolled diabetes (A1C>6.8%) at baseline (43).
Behavioral Interventions
Significant weight loss can be attained with lifestyle programs that achieve a 500–750 kcal/day energy deficit, which in most cases is approximately 1,200–1,500 kcal/day for women and 1,500–1,800 kcal/day for men, adjusted for the indi-vidual’s baseline body weight. Clinical benefits typically begin upon achieving 3–5% weight loss (19,44), and the bene-fits of weight loss are progressive; more intensive weight loss goals (>5%, >7%,
>15%, etc.) may be pursued if needed to achieve further health improvements and/or if the patient is more motivated and more intensive goals can be feasibly and safely attained.
Dietary interventions may differ by macronutrient goals and food choices as long as they create the necessary energy deficit to promote weight loss (19,45–47). Use of meal replacement plans prescribed by trained practition-ers, with close patient monitoring, can be beneficial. Within the intensive life-style intervention group of the Look AHEAD trial, for example, use of a par-tial meal replacement plan was associ-ated with improvements in diet quality and weight loss (44). The diet choice should be based on the patient’s health status and preferences, including a determination of food availability and other cultural circumstances that could affect dietary patterns (48).
Intensive behavioral interventions should include$16 sessions during the initial 6 months and focus on dietary changes, physical activity, and behavioral
strategies to achieve an500–750 kcal/
day energy deficit. Interventions should be provided by trained interventionists in either individual or group sessions (44). Assessing an individual’s motivation level, life circumstances, and willingness to implement behavioral changes to achieve weight loss should be considered along with medical status when weight loss interventions are recommended and ini-tiated (37,49).
Patients with type 2 diabetes and over-weight or obesity who have lost over-weight should be offered long-term ($1 year) comprehensive weight loss maintenance programs that provide at least monthly contact with trained interventionists and focus on ongoing monitoring of body weight (weekly or more frequently) and/
or other self-monitoring strategies such as tracking intake, steps, etc.; continued focus on dietary and behavioral changes;
and participation in high levels of physical activity (200–300 min/week) (50). Some commercial and proprietary weight loss programs have shown promising weight loss results, though most lack evidence of effectiveness, many do not satisfy guide-line recommendations, and some pro-mote unscientific and possibly dangerous practices (51,52).
When provided by trained practitioners in medical settings with ongoing monitor-ing, short-term (generally up to 3 months) intensive dietary intervention may be pre-scribed for carefully selected patients, such as those requiring weight loss prior to surgery and those needing greater weight loss and glycemic improvements.
When integrated with behavioral support and counseling, structured very-low-calo-rie diets, typically 800–1,000 kcal/day utilizing high-protein foods and meal replacement products, may increase the pace and/or magnitude of initial weight loss and glycemic improvements com-pared with standard behavioral interven-tions (20,21). As weight regain is common,
Table 8.1—Treatment options for overweight and obesity in type 2 diabetes
BMI category (kg/m2)
Treatment 25.0–26.9 (or 23.0–24.9*) 27.0–29.9 (or 25.0–27.4*) $30.0 (or $27.5*)
Diet, physical activity, and behavioral counseling † † †
Pharmacotherapy † †
Metabolic surgery †
*Recommended cutpoints for Asian American individuals (expert opinion).†Treatment may be indicated for select motivated patients.
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such interventions should include long-term, comprehensive weight maintenance strategies and counseling to maintain weight loss and behavioral changes (53,54).
Despite widespread marketing and exorbitant claims, there is no clear evi-dence that dietary supplements (such as herbs and botanicals, high-dose vitamins and minerals, amino acids, enzymes, anti-oxidants, etc.) are effective for obesity management or weight loss (55–57). Sev-eral large systematic reviews show that most trials evaluating dietary supple-ments for weight loss are of low quality and at high risk for bias. High-quality pub-lished studies show little or no weight loss benefits. In contrast, vitamin/mineral (e.g., iron, vitamin B12, vitamin D) supple-mentation may be indicated in cases of documented deficiency, and protein sup-plements may be indicated as adjuncts to medically supervised weight loss regimens.
Health disparities adversely affect peo-ple who have systematically experienced greater obstacles to health based on their race or ethnicity, socioeconomic status, gender, disability, or other factors. Over-whelming research shows that these dis-parities may significantly affect health outcomes, including increasing the risk for obesity, diabetes, and diabetes-related complications. Health care providers should evaluate systemic, structural, and socioeconomic factors that may impact food choices, access to healthful foods, and dietary patterns; behavioral patterns, such as neighborhood safety and availabil-ity of safe outdoor spaces for physical activity; environmental exposures; access to health care; social contexts; and, ulti-mately, diabetes risk and outcomes. For a detailed discussion of social determinants of health, refer to“Social Determinants of Health: A Scientific Review” (58).
PHARMACOTHERAPY Recommendations
8.13 When choosing glucose-low-ering medications for peo-ple with type 2 diabetes and overweight or obesity, con-sider the medication’s effect on weight.B
8.14 Whenever possible, minimize medications for comorbid con-ditions that are associated with weight gain.E
8.15 Weight loss medications are effective as adjuncts to diet, physical activity, and behavioral counseling for selected people with type 2 diabetes and BMI
$27 kg/m2. Potential benefits and risks must be considered.A 8.16 If a patient’s response to weight loss medication is effective (typically defined as
>5% weight loss after 3 months’ use), further weight loss is likely with continued use. When early response is insufficient (typically <5%
weight loss after 3 months’ use) or if there are significant safety or tolerability issues, consider discontinuation of the medication and evaluate alternative medications or treatment approaches.A
Glucose-Lowering Therapy
A meta-analysis of 227 randomized con-trolled trials of glucose-lowering treat-ments in type 2 diabetes found that A1C changes were not associated with base-line BMI, indicating that people with obe-sity can benefit from the same types of treatments for diabetes as normal-weight patients (59). As numerous effective med-ications are available, when considering medication regimens health care pro-viders should consider each medication’s effect on weight. Agents associated with varying degrees of weight loss include metformin, a-glucosidase inhibitors, sodium–glucose cotransporter 2 inhibi-tors, glucagon-like peptide 1 receptor agonists, and amylin mimetics. Dipeptidyl peptidase 4 inhibitors are weight neutral.
In contrast, insulin secretagogues, thiazo-lidinediones, and insulin are often associ-ated with weight gain (see Section 9,
“Pharmacologic Approaches to Glycemic Treatment,” https://doi.org/10.2337/
dc22-S009).
Concomitant Medications
Providers should carefully review the patient’s concomitant medications and, whenever possible, minimize or provide alternatives for medications that promote weight gain. Examples of medications associated with weight gain include anti-psychotics (e.g., clozapine, olanzapine, ris-peridone, etc.), some antidepressants
(e.g., tricyclic antidepressants, some selective serotonin reuptake inhibitors, and monoamine oxidase inhibitors), glu-cocorticoids, injectable progestins, some anticonvulsants (e.g., gabapentin, prega-balin), and possibly sedating antihist-amines and anticholinergics (60).
Approved Weight Loss Medications The U.S. Food and Drug Administration (FDA) has approved medications for both short-term and long-term weight man-agement as adjuncts to diet, exercise, and behavioral therapy. Nearly all FDA-approved medications for weight loss have been shown to improve glycemic control in patients with type 2 diabetes and delay progression to type 2 diabetes in patients at risk (22). Phentermine and other older adrenergic agents are indi-cated for short-term (#12 weeks) treat-ment (61). Five weight loss medications are FDA approved for long-term use (>12 weeks) in adult patients with BMI
$27 kg/m2 with one or more obesity-associated comorbid condition (e.g., type 2 diabetes, hypertension, and/or dyslipi-demia) who are motivated to lose weight (22). Medications approved by the FDA for the treatment of obesity, summarized in Table 8.2, include orlistat, phenter-mine/topiramate ER, naltrexone/bupro-pion ER, liraglutide 3 mg, and semaglutide 2.4 mg. (In addition, setmelanotide, a mel-anocortin-4 receptor agonist, is approved for use in cases of rare genetic mutations resulting in severe hyperphagia and extreme obesity, such as leptin receptor deficie-ncy and proopiomelanocortin defi-ciency.) In principle, medications help improve adherence to dietary recommen-dations, in most cases by modulating appetite or satiety. Providers should be knowledgeable about the product label and balance the potential benefits of suc-cessful weight loss against the potential risks of the medication for each patient.
These medications are contraindicated in women who are pregnant or actively try-ing to conceive and not recommended for use in women who are nursing. Women of reproductive potential should receive counseling regarding the use of reliable methods of contraception. Of note, while weight loss medications are often used in patients with type 1 diabetes, clinical trial data in this population are limited.
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Table8.2—MedicationsapprovedbytheFDAforthetreatmentofobesityinadults 1-Year(52-or56-week)meanweight loss(%lossfrombaseline) MedicationnameTypicaladult maintenancedose Averagewholesale price(30-daysupply) (130) NationalAverage DrugAcquisition Cost(30-day supply)(131)Treatmentarms
Weightloss (%lossfrom baseline)Commonsideeffects (132–136)Possiblesafetyconcerns/ considerations(132–136) Short-termtreatment(##12weeks) Sympathomimeticamineanorectic Phentermine(137)8–37.5mgq.d.*$5–$44(37.5mg dose)
$3(37.5mg dose) 15mgq.d.†6.1Drymouth,insomnia, dizziness,irritability, increasedbloodpressure, elevatedheartrate
Contraindicatedforusein combinationwithmonoamine oxidaseinhibitors7.5mgq.d.†5.5 PBO1.2 Long-termtreatment(>12weeks) Lipaseinhibitor Orlistat(3)60mgt.i.d.(OTC) 120mgt.i.d.(Rx)
$41−$82 $823
$41 $659
120mgt.i.d.‡ PBO
9.6 5.6Abdominalpain,flatulence, fecalurgencyPotentialmalabsorptionoffat- solublevitamins(A,D,E,K) andofcertainmedications (e.g.,cyclosporine,thyroid hormone,anticonvulsants,etc.) Rarecasesofsevereliverinjury reported Cholelithiasis Nephrolithiasis Sympathomimeticamineanorectic/antiepilepticcombination Phentermine/ topiramateER(138)
7.5mg/46mgq.d.§$223(7.5mg/46mg dose)
$179(7.5mg/46 mgdose) 15mg/92mg q.d.jj9.8Constipation,paresthesia, insomnia, nasopharyngitis, xerostomia,increased bloodpressure
Contraindicatedforusein combinationwithmonoamine oxidaseinhibitors Birthdefects Cognitiveimpairment Acuteangle-closureglaucoma
7.5mg/46mg q.d.jj7.8 PBO1.2 Opioidantagonist/antidepressantcombination Naltrexone/ bupropionER(15)
16mg/180mgb.i.d.$364$29116mg/180mgb.i.d.5.0Constipation,nausea, headache,xerostomia, insomnia,elevatedheart rateandbloodpressure
Contraindicatedinpatientswith uncontrolledhypertension and/orseizuredisorders Contraindicatedforusewith chronicopioidtherapy Acuteangle-closureglaucoma
PBO1.8 Blackboxwarning: Riskofsuicidalbehavior/ ideationinpeopleyounger than24yearsoldwhohave depression Continuedonp.S118
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Table8.2—Continued 1-Year(52-or56-week)meanweight loss(%lossfrombaseline) MedicationnameTypicaladult maintenancedose Averagewholesale price(30-daysupply) (130) NationalAverage DrugAcquisition Cost(30-day supply)(131)Treatmentarms
Weightloss (%lossfrom baseline)Commonsideeffects (132–136)Possiblesafetyconcerns/ considerations(132–136) Glucagon-likepeptide1receptoragonist Liraglutide(16)**3mgq.d.$1,619$1,2963.0mgq.d. 1.8mgq.d. PBO
6.0 4.7 2.0
Gastrointestinalsideeffects (nausea,vomiting, diarrhea,esophageal reflux),injectionsite reactions,elevatedheart rate,hypoglycemia
Pancreatitishasbeenreported inclinicaltrialsbutcausality hasnotbeenestablished. Discontinueifpancreatitisis suspected. Usecautioninpatientswith kidneydiseasewheninitiating orincreasingdosedueto potentialriskofacutekidney injury Blackboxwarning: RiskofthyroidC-celltumors inrodents;humanrelevance notdetermined Semaglutide(139)2.4mgonceweekly$1,619$1,3022.4mgweekly PBO9.6 3.4
Gastrointestinalsideeffects (nausea,vomiting, diarrhea,esophageal reflux),injectionsite reactions,elevatedheart rate,hypoglycemia
Pancreatitishasbeen reportedinclinicaltrials,but causalityhasnotbeen established.Discontinueif pancreatitisissuspected. Blackboxwarning: RiskofthyroidC-celltumors inrodents;humanrelevance notdetermined Allmedicationsarecontraindicatedinwomenwhoareormaybecomepregnant.Womenofreproductivepotentialmustbecounseledregardingtheuseofreliablemethodsofcontraception.Select safetyandsideeffectinformationisprovided;foracomprehensivediscussionofsafetyconsiderations,pleaserefertotheprescribinginformationforeachagent.b.i.d.,twicedaily;ER,extendedrelease; N/A,notapplicable;OTC,overthecounter;PBO,placebo;q.d.,daily;Rx,prescription;t.i.d.,threetimesdaily.*Uselowesteffectivedose;maximumappropriatedoseis37.5mg.†Durationoftreatment was28weeksinageneraladultpopulationwithobesity.**Agenthasdemonstratedcardiovascularsafetyinadedicatedcardiovascularoutcometrial(140).‡Enrolledparticipantshadnormal(79%)or impaired(21%)glucosetolerance.§Maximumdose,dependingonresponse,is15mg/92mgq.d.jjApproximately68%ofenrolledparticipantshadtype2diabetesorimpairedglucosetolerance.
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Assessing Efficacy and Safety
Upon initiating weight loss medication, assess efficacy and safety at least monthly for the first 3 months and at least quarterly thereafter. Modeling from published clinical trials consistently shows that early responders have improved long-term outcomes (62–64). Unless clini-cal circumstances (such as poor tolerabil-ity) or other considerations (such as financial expense or patient preference) suggest otherwise, those who achieve sufficient early weight loss upon starting a chronic weight loss medication (typi-cally defined as >5% weight loss after 3 months’ use) should continue the medi-cation. When early use appears ineffec-tive (typically <5% weight loss after 3 months’ use), it is unlikely that continued use will improve weight outcomes; as such, it should be recommended to dis-continue the medication and consider other treatment options.
MEDICAL DEVICES FOR WEIGHT LOSS
While gastric banding devices have fallen out of favor in recent years, since 2015 several minimally invasive medical devices have been approved by the FDA for short-term weight loss, including implanted gastric balloons, a vagus nerve stimulator, and gastric aspiration therapy (65). Given the current high cost, limited insurance coverage, and paucity of data in people with diabetes, medical devices for weight loss are rarely utilized at this time, and it remains to be seen how they may be used in the future (66).
Recently, an oral hydrogel (Plenity) has been approved for long-term use in those with BMI>25 kg/m2 to simulate the space-occupying effect of implant-able gastric balloons. Taken with water 30 min before meals, the hydrogel expands tofill a portion of the stomach volume to help decrease food intake dur-ing meals. Though average weight loss is relatively small (2–3% greater than pla-cebo), the subgroup of participants with prediabetes or diabetes at baseline had improved weight loss outcomes (8.1%
weight loss) compared with the overall treatment (6.4% weight loss) and pla-cebo (4.4% weight loss) groups (67).
METABOLIC SURGERY Recommendations
8.17 Metabolic surgery should be a recommended option to treat type 2 diabetes in screened sur-gical candidates with BMI$40 kg/m2 (BMI $37.5 kg/m2 in Asian Americans) and in adults with BMI 35.0–39.9 kg/m2 (32.5–37.4 kg/m2 in Asian Americans) who do not achieve durable weight loss and improvement in comorbidities (including hyperglycemia) with nonsurgical methods.A 8.18 Metabolic surgery may be
con-sidered as an option to treat type 2 diabetes in adults with BMI 30.0–34.9 kg/m2 (27.5–32.4 kg/m2 in Asian Americans) who do not achieve durable weight loss and improvement in comorbidities (including hyperglycemia) with nonsurgical methods.A 8.19 Metabolic surgery should be
performed in high-volume cen-ters with multidisciplinary teams knowledgeable about and expe-rienced in the management of obesity, diabetes, and gastroin-testinal surgery.E
8.20 People being considered for metabolic surgery should be evaluated for comorbid psycho-logical conditions and social and situational circumstances that have the potential to inter-fere with surgery outcomes.B 8.21 People who undergo metabolic
surgery should receive long-term medical and behavioral support and routine monitoring of micronutrient, nutritional, and metabolic status.B 8.22 If postbariatric hypoglycemia is
suspected, clinical evaluation should exclude other potential disorders contributing to hypo-glycemia, and management includes education, medical nutrition therapy with a dieti-tian experienced in postbariatric hypoglycemia, and medication treatment, as needed.A Contin-uous glucose monitoring should be considered as an important adjunct to improve safety by
alerting patients to hypoglyce-mia, especially for those with severe hypoglycemia or hypo-glycemia unawareness.E 8.23 People who undergo metabolic
surgery should routinely be evaluated to assess the need for ongoing mental health serv-ices to help with the adjustment to medical and psychosocial changes after surgery.C
Surgical procedures for obesity treat-ment—often referred to interchange-ably as bariatric surgery, weight loss surgery, metabolic surgery, or meta-bolic/bariatric surgery—can promote significant and durable weight loss and improve type 2 diabetes. Given the magnitude and rapidity of improvement of hyperglycemia and glucose homeo-stasis, these procedures have been suggested as treatments for type 2 dia-betes even in the absence of severe obesity and will be referred to here as
“metabolic surgery.”
A substantial body of evidence, includ-ing data from numerous large cohort studies and randomized controlled (non-blinded) clinical trials, demonstrates that metabolic surgery achieves superior gly-cemic control and reduction of cardiovas-cular risk in patients with type 2 diabetes and obesity compared with nonsurgical intervention (17). In addition to improv-ing glycemia, metabolic surgery reduces the incidence of microvascular disease (68), improves quality of life (69–71), decreases cancer risk, and improves car-diovascular disease risk factors and long-term cardiovascular events (72–83).
Cohort studies that match surgical and nonsurgical subjects strongly suggest that metabolic surgery reduces all-cause mortality (84,85).
The overwhelming majority of proce-dures in the U.S. are vertical sleeve gas-trectomy (VSG) and Roux-en-Y gastric bypass (RYGB). Both procedures result in an anatomically smaller stomach pouch and often robust changes in enteroendocrine hormones. In VSG,
80% of the stomach is removed, leav-ing behind a long, thin sleeve-shaped pouch. RYGB creates a much smaller stomach pouch (roughly the size of a
“walnut”), which is then attached to the
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distal small intestine, thereby bypassing the duodenum and jejunum. (Fig. 8.1.)
Several organizations recommend lowering the BMI criteria for metabolic surgery to 30 kg/m2 (27.5 kg/m2 for Asian Americans) for people with type 2 diabetes who have not achieved suf fi-cient weight loss and improved comor-bidities (including hyperglycemia) with reasonable nonsurgical treatments (86–93). Studies have documented dia-betes remission after 1–5 years in 30–63% of patients with RYGB (17,94).
Most notably, the Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently (STAMPEDE) trial, which randomized 150 participants with uncontrolled diabetes to receive either metabolic surgery or medical treatment, found that 29% of those treated with RYGB and 23% treated with VSG achieved A1C of 6.0% or lower after 5 years (95). Available data suggest an erosion of diabetes remission over time (96); at least 35–50% of patients who initially achieve remission of diabetes eventually experience recurrence. Still, the median disease-free period among such individuals following RYGB is 8.3 years (97,98), and the majority of those who undergo surgery maintain substan-tial improvement of glycemic control from baseline for at least 5–15 years (69,73,74,95,98–101).
Exceedingly few presurgical predic-tors of success have been identified, but younger age, shorter duration of diabetes (e.g., <8 years) (70), and lesser severity of diabetes (better gly-cemic control, nonuse of insulin) are associated with higher rates of
diabetes remission (70,73,100,102).
Greater baseline visceral fat area may also predict improved postoperative outcomes, especially among Asian American patients with type 2 diabe-tes, who typically have greater visceral fat compared with Caucasians (103).
Although surgery has been shown to improve the metabolic profiles of patients with type 1 diabetes, larger and longer-term studies are needed to determine the role of metabolic surgery in such patients (104).
Whereas metabolic surgery has greater initial costs than nonsurgical obe-sity treatments, retrospective analyses and modeling studies suggest that sur-gery may be effective or even cost-saving for individuals with type 2 diabe-tes. However, these results are largely dependent on assumptions about the long-term effectiveness and safety of the procedures (105,106).
Potential Risks and Complications The safety of metabolic surgery has improved significantly with continued refinement of minimally invasive (laparo-scopic) approaches, enhanced training and credentialing, and involvement of multi-disciplinary teams. Perioperative mortality rates are typically 0.1–0.5%, similar to those of common abdominal procedures such as cholecystectomy or hysterectomy (107–111). Major complications occur in 2–6% of those undergoing metabolic sur-gery, which compares favorably with the rates for other commonly performed elec-tive operations (111). Postsurgical recovery times and morbidity have also dramatically declined. Minor complications and need
for operative reintervention occur in up to 15% (107–116). Empirical data suggest that proficiency of the operating surgeon and surgical team is an important factor for determining mortality, complications, reoperations, and readmissions (117).
Accordingly, metabolic surgery should be performed in high-volume centers with multidisciplinary teams experienced in the management of diabetes, obesity, and gas-trointestinal surgery.
Beyond the perioperative period, lon-ger-term risks include vitamin and min-eral deficiencies, anemia, osteoporosis, dumping syndrome, and severe hypogly-cemia (118). Nutritional and micronutri-ent deficiencies and related complications occur with variable frequency depending on the type of procedure and require routine monitoring of micronutrient and nutritional status and lifelong vitamin/
nutritional supplementation (118). Dump-ing syndrome usually occurs shortly (10–30 min) after a meal and may pre-sent with diarrhea, nausea, vomiting, pal-pitations, and fatigue; hypoglycemia is usually not present at the time of symp-toms but in some cases may develop sev-eral hours later.
Postbariatric hypoglycemia (PBH) can occur with RYGB, VSG, and other gastro-intestinal procedures and may severely impact quality of life (119–121). PBH is driven in part by altered gastric emptying of ingested nutrients, leading to rapid intestinal glucose absorption and exces-sive postprandial secretion of glucagon-like peptide 1 and other gastrointestinal peptides. As a result, overstimulation of insulin release and a sharp drop in plasma glucose occurs, most commonly 1–3 h after a high-carbohydrate meal.
Symptoms range from sweating, tremor, tachycardia, and increased hunger to impaired cognition, loss of conscious-ness, and seizures. In contrast to dump-ing syndrome, which often occurs soon after surgery and improves over time, PBH typically presents >1 year postsur-gery. Diagnosis is primarily made by a thorough history; detailed records of food intake, physical activity, and symp-tom patterns; and exclusion of other potential causes (e.g., malnutrition, side effects of medications or supplements, dumping syndrome, insulinoma). Initial management includes patient education to facilitate reduced intake of rapidly digested carbohydrates while ensuring adequate intake of protein and healthy
Figure 8.1—A: Vertical sleeve gastrectomy. B: Roux-en-Y gastric bypass surgery. Images reprinted from National Institute of Diabetes and Digestive and Kidney Diseases (141).
S120 Obesity and Weight Management for Type 2 Diabetes Diabetes Care Volume 45, Supplement 1, January 2022