SUN-631 - What Type of Diabetes Does This Patient Have?

Background

Diabetes mellitus (DM) is traditionally classified into type 1, characterized by the autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency, and type 2, defined by increasing insulin resistance leading to insulin deficiency. However, there is growing clinical evidence that shows that DM can exist along a spectrum, with patients presenting with a mix of both type 1 and type 2 features. We present a case of DM with overlapping features of type 1 and type 2 diabetes mellitus (DMT2), highlighting the clinical complexity of treating this disease.

Case Presentation

A 78- year- old male with a past medical history of hypothyroidism, hypertension, hyperlipidemia, gout, benign prostate hyperplasia presented to establish care with Endocrinology for evaluation and management of DM. Per patient, he was diagnosed with DMT2 approximately 10 years ago during a general wellness examination with his primary care physician. His DMT2 was initially well-controlled with oral medications of empagliflozin and metformin, but within the past year his glycemic control had worsened despite escalation of oral medications and the addition of tirzepatide weekly injections. The patient denied family history of DM or autoimmune disorders, but did endorse exposure to a hazardous material (likely Agent Orange) while serving in the military in Vietnam. On laboratory testing, he was found to have an elevated Glutamic Acid Decarboxylase- 65 antibody (GAD-65) level of >250 (normal < 5) with an elevated C-peptide level of 5.00 ng/mL (normal 0.3- 3.3). Insulin glargine 20 units daily subcutaneously was added to the patient’s DM medication regimen, and patient’s continuous glucose monitor data showed improved glycemic control with 81% of glucose readings in target range. Repeat laboratory testing showed hemoglobin A1C decreased from 7.4% to 5.8%.

Discussion

“Atypical” forms of DM need to be recognized and differentiated from the “usual” forms of DM, as treatment and management must be individually tailored in order to achieve optimal glycemic control. The emergence of these “atypical” forms of DM such as latent autoimmune diabetes in adults (LADA), maturity- onset DM of the young (MODY), ketosis- prone DM, and pancreatogenic DM may often present as a challenging diagnosis with unusual clinical features that require an interdisciplinary approach.

Conclusion

This case highlights the growing spectrum of DM and emphasizes the importance of recognizing and treating patients who present with features not consistent with only type 1 or type 2 DM. Management remains difficult and must be individually developed for each patient.

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