SAT-710 - Assessing Alignment between Obesity Severity and Referral Patterns to Endocrinology and Bariatric Surgery using the Edmonton Obesity Staging System

Background:
Obesity severity is poorly captured by body mass index (BMI) alone. The Edmonton Obesity Staging System (EOSS) incorporates obesity-related comorbidities and functional impairment to independently predict morbidity and mortality. While bariatric surgery is the most effective therapy for advanced obesity-related diseases, referral decisions are often made without a standardized assessment of obesity severity. The expanding availability of effective medications has further increased referrals to endocrinology, underscoring the need for standardized approaches to guide treatment. Whether real-world referral patterns align with validated measures of obesity severity remains unclear. We examined whether referral patterns aligned with obesity severity as defined by EOSS and hypothesized that patients with more severe obesity would be referred to bariatric surgery.

Methods:
We conducted a retrospective matched case-control study of adults with obesity (ages 18-70 years, BMI >30 kg/m²) seen for initial weight management consultation in endocrinology (n=100) or bariatric surgery (n=200) clinics at a tertiary care center. Patients were matched 2:1 for age, sex, and BMI using propensity-score matching. Overall EOSS score was determined by the highest stage across obesity-related EOSS domains. Conditional logistic regression was used to assess associations between EOSS stage and referral destination. Results are presented as odds ratios with 95% confidence intervals.

Results:
Both groups were similar with respect to age, sex, and BMI, consistent with matching. However, patients seen in endocrinology were more likely to be White and commercially insured, whereas patients referred to bariatric surgery were more likely to be Hispanic or Black and publicly insured. Patients with moderate obesity severity (EOSS stage 2) had significantly lower odds of referral to endocrinology compared with bariatric surgery (OR 0.36 [0.17-0.77], p< 0.01). In contrast, patients with severe obesity (EOSS stage 3) had similar odds of referral to either clinic (OR 1.31 [0.40-4.28]). Hypertension was the only EOSS subcategory independently associated with referral destination, with lower odds of endocrinology referral (OR 0.55 [0.32-0.93], p=0.03).

Conclusions:
Referral patterns for obesity care do not consistently align with overall severity as defined by EOSS. Although the drivers of these patterns cannot be determined from this analysis, they warrant future study, including the roles of referrer knowledge, access, and patient preferences. Without standardized, disease-based severity assessment, variability in referral practices may contribute to inequitable access to effective obesity therapies. As obesity care evolves beyond BMI-based models, systematic approaches to severity assessment will be critical to support equitable, patient-centered treatment selection.

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