SAT-775 Clinical Characteristics and Treatment Patterns in MEN1-Associated Primary Hyperparathyroidism: A Nationwide Cohort Study

Abstract Disclosure: K. Kim: None. M. Yu: None. Y. Hwang: None. Y. Rhee: None. Multiple Endocrine Neoplasia Type 1-associated Primary Hyperparathyroidism (MEN1-PHPT) is a rare but significant endocrine disorder with high recurrence rates and increased systemic complications. Despite its distinct pathophysiology from sporadic PHPT, large-scale studies on MEN1-PHPT are limited. This study evaluates clinical patterns and complication risks in MEN1-PHPT using nationwide cohort data from the Korean National Health Insurance Service (2002–2020). MEN1-PHPT cases were identified using two operational definitions based on ICD-10 codes and procedures. Definition 1 included patients with at least one D44.8 diagnosis, excluding medullary thyroid carcinoma. Definition 2 included patients meeting at least two criteria: management for primary hyperparathyroidism, pituitary adenomas, or neuroendocrine tumors. A total of 241 MEN1-PHPT patients were matched 1:10 by age, sex, and index year with controls (n = 2,410). Clinical characteristics, comorbidities, and treatment patterns, including parathyroidectomy trends, were analyzed. Adjusted odds ratios (ORs) assessed complication risks. The mean PHPT diagnosis age was 43.6 years (SD 14.2), with 62.2% females, matching control demographics. MEN1-PHPT patients had a higher Charlson Comorbidity Index (2.42 vs. 0.53, p < 0.001) and greater prevalence of diabetes (24.5% vs. 5.1%), hypertension (39.8% vs. 16.2%), dyslipidemia (19.1% vs. 10.9%), osteoporosis (11.2% vs. 0.6%), cardiovascular disease (10.4% vs. 3.6%), and cancer (30.7% vs. 1.3%). Parathyroidectomy (PTX) rates increased over time, with multi-gland surgeries surpassing single-gland procedures by 2016. Repeat surgeries rose, reflecting MEN1-PHPT's recurrent nature. Complication risks were significantly higher in MEN1-PHPT patients. Renal complications had an OR of 11.03 (95% CI: 7.59–16.03), with elevated risks for kidney stones (OR 9.71) and ESRD (OR 12.27). Skeletal complications included non-vertebral fractures (OR 2.17, p = 0.004) and osteoporotic fractures (OR 1.76, p = 0.021). Cardiovascular risks were markedly elevated (OR 32.75, p < 0.001), with cerebrovascular disease showing the highest risk (OR 54.80, p < 0.001). Atrial fibrillation was also significant (OR 2.45, p = 0.010), while myocardial infarction and heart failure risks were elevated but not statistically significant. In summary, MEN1-PHPT patients have a significantly higher burden of comorbidities and complications, requiring more extensive and recurrent surgeries. The trend toward multi-gland and repeat surgeries reflects the disease's complexity. These findings emphasize the need for tailored treatments and long-term monitoring to mitigate complications and improve outcomes. Presentation: Saturday, July 12, 2025