University of Wisconsin–Madison Medical College of Wisconsin

The Influence of Falsely Low HbA1c Levels in Diabetes Patients With Hereditary Hemorrhagic Telangiectasia: The Need for Alternative Diagnostic Approaches

Olivia Foley, BS; Abubakar Tauseef, MD; Jacob Brenner, DO

WMJ. 2026;125(2):309-311. Published June 2, 2026.

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ABSTRACT

Introduction: Hereditary hemorrhagic telangiectasia (HHT) causes various age-related symptoms, including epistaxis, telangiectasia, and anemia. These symptoms often require a variety of treatments, including iron supplementation and blood transfusions. The resulting anemia can lead to atypical presentations of comorbidities, such as diabetes.

Case Presentation: A 46-year-old Hispanic woman with a history of HHT presented for diabetes evaluation due to asymptomatic, elevated nonfasting blood glucose despite normal hemoglobin A1c (HbA1c) levels. Following initiation of continuous glucose monitoring and metformin (500 mg twice daily), her blood glucose levels improved significantly.

Discussion: Patients with HHT are more likely to develop iron deficiency anemia and anemia secondary to chronic blood loss, rendering HbA1c levels unreliable for diagnosing diabetes.

Conclusions: Clinicians should consider the impact of HHT-related anemia when monitoring patients for diabetes. Alternative diagnostic methods are necessary to prevent delays in diagnosis and treatment.


Author affiliations: Department of Internal Medicine, Creighton University School of Medicine, Omaha, Nebraska (Brenner, Foley, Tauseef).
Corresponding author:
Olivia Foley, 7500 Mercy Rd, Omaha, NE; email oaf34218@creighton.edu; ORCID ID 0009-0009-4318-4202
Financial disclosures: None declared.
Funding/support:
None declared.
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