International expert consensus statements on surgery for T2DM

An International panel of experts has published 43 statements on the nature, terminology and mechanisms of action of metabolic and bariatric surgery (MBS), which the panel believes will guide clinicians on various aspects of MBS for T2DM, also grades the quality of the available evidence for each of the proposed statements.

The panel embarked on a Delphi consensus-building exercise to propose an evidence-based expert consensus covering various aspects of MBS in patients with T2DM. They defined the scope of the exercise and proposed statements and surveyed the literature through electronic databases. The literature summary and voting process were conducted by 52 experts, who evaluated 44 statements. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

They found that the currently available scores for predicting remission of T2DM after surgery are not robust enough for routine clinical use, and there is a need for further research to enable more personalized treatment. Additionally, they agreed that metabolic surgery for T2DM is cost-effective, and MBS procedures for treating T2DM vary in their safety and efficacy. According to the results of this expert consensus, the recommendations around metabolic surgery for T2DM are summarised in Table 1.

Table 1: Recommendations around metabolic surgery for T2DM

The statements and recommendations covered nine different aspects, namely I-Nature, Terminology and Mechanisms of Action, II-Predictors of Remission, III-Preoperative Diabetic Control, IV-Perioperative Care, Monitoring and Special Considerations, V-Care Pathways and Logistics of Service, VI- Accurate Classification of Diabetes Mellitus, VII-Surgical Considerations, VIII-Communication with Primary Care and Extended Follow-up, and IX-Remission and Recurrence.

In summary:

• Ninety-five per cent agreed that surgery has a strong evidence-based role in treating some patients with T2DM, and 94% agreed that metabolic surgery for T2DM works through both weight-loss-dependent and weight-loss-independent mechanisms.

• The expert panel recommended using the term "Metabolic Surgery for T2DM" as a common descriptor for surgery aimed at treating people with T2DM.

• Ninety-six per cent of the panel agreed that the beneficial impact of metabolic surgery for T2DM depends on many factors.

• Additionally, 86% agreed that metabolic surgery for T2DM only has a role in individuals with obesity, and the currently available scores for predicting remission of T2DM after surgery are not robust enough for routine clinical use.

• However, 92% agreed on the need to optimize glycemic control to an HbA1c level of ≤ 69 mmol/mol (≈ 8.5%), and 83% agreed that HbA1c > 69 mmol/mol should not be considered an absolute contraindication for patients undergoing surgery for T2DM.

• The experts agreed on six statements related to perioperative care and monitoring and recommended that patients undergoing metabolic surgery for T2DM should be reviewed by a diabetologist for perioperative management of diabetes.

• Additionally, they recommended frequent glucose and blood pressure monitoring in the early postoperative phase.

Furthermore, there was complete consensus (100%) on the barriers that prevent patients from accessing surgery for diabetes, including insufficient awareness of the benefits and risks of surgery amongst many healthcare professionals, insufficient awareness amongst patients on the safety and efficacy of surgery, lack of funding or insurance coverage for surgery, mandatory weight loss targets, lack of capacity for delivering surgery to eligible patients, weight bias towards access to healthcare, stigma, and shame of obesity.

A complete consensus was achieved that the referral criteria for surgery should not be based on BMI alone, and the patient's other obesity-associated medical and mental health conditions and quality of life should be considered.

The panel also recommended considering alternative diagnoses for T2DM, such as T1DM or Maturity Onset Diabetes of Young (MODY), before referring patients for surgery. Additionally, surgery can be an option in selected patients with T1DM or Latent Autoimmune Diabetes in Adults (LADA) who also meet BMI criteria for MBS.

Regarding the surgical considerations, 86% agreed that gastric balloons have no role for patients seeking metabolic surgery for T2DM apart from being used as a bridge to facilitate surgery, and 83% agreed that there is currently insufficient evidence to suggest a role for endoscopic sleeve gastroplasty in these patients.

Ninety-four per cent agreed that the patients should be followed up in a multidisciplinary environment for the first two years after surgery. The panel recommends that remission is defined as an HbA1c of < 48 mmol/mol (< 6.5%) for at least three months in the absence of glucose-lowering pharmacotherapy.

The findings were reported in the paper, 'International expert consensus on surgery for type 2 diabetes mellitus', published in the BMC Endocrine Disorders.

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