Gaps in Referral to Bariatric Surgery for Patients With Type 2 Diabetes Seen in Endocrinology Clinics

One-third of adults in Canada are overweight and 26.8% experience obesity. Bariatric surgery confers effective weight loss and reduces obesity-related complications, including type 2 diabetes, but remains an underutilized treatment. Our objective in this study was to determine whether a gap exists in bariatric program referrals for patients with type 2 diabetes seen in endocrinology clinics at an ambulatory tertiary care hospital in Toronto, Canada.

A retrospective chart review was conducted of 843 consecutive patients with type 2 diabetes in endocrinology clinics between January 1, 2015 and December 31, 2020. Inclusion criteria were age ≥18 years, type 2 diabetes and body mass index (BMI)>35 kg/m². Exclusion criteria were recent active cancer, uncontrolled psychiatric disease or active substance use disorder within 6 months of the initial visit. Referrals to bariatric surgery were assessed within a 5-year follow-up period and compared with baseline referral rates from the Ontario Bariatric Network (OBN). An online survey of 48 endocrinologists in Toronto, Ontario, was also conducted to assess physician-level barriers to referral.

The proportion of patients with class II obesity (BMI>35 kg/m²) and type 2 diabetes meeting the eligibility criteria for bariatric referral was 4.6% (n=38). A documented discussion about bariatric surgery occurred with 7 (18.0%) of these eligible patients, and 1 patient (2.6%) was referred for surgery. Aside from surgical referrals, only 2.6% of eligible patients were referred to cognitive-behavioural therapy, 36.8% were initiated on obesity pharmacotherapy and 42.1% were referred to a dietitian. Baseline OBN data demonstrated that most surgical referrals (n=6,360) were from family physicians (65.0%) and only 8.8% were from a medical specialist. Eight percent of surveyed endocrinologists reported that they discussed bariatric surgery with at least half of their eligible patients. The most frequent barrier to discussing bariatric surgery during visits was time constraints. Physicians identified that simplifying the referral process and providing bariatric surgery handouts would be helpful interventions to improve referral rates.

Our gap analysis demonstrated a low bariatric surgery referral rate by tertiary care endocrinologists. Our study also identified a large gap in the appropriate treatment of obesity with poor utilization of behavioural, lifestyle and pharmacotherapy practices. As obesity and diabetes rates increase, better education, training and knowledge translation will be necessary to overcome weight bias and prioritize obesity management.