title: Falsely decreased HbA1c in a type 2 diabetic patient treated with dapsone.
abstract: Glycated hemoglobin A1c (HbA1c) is an important indicator of glycemic control. The current recommendation for glycemic control based on HbA1c values has been widely accepted. However, HbA1c values depend on the lifespan of erythrocytes and the assay methods used. Here, we report the case of a patient with type 2 diabetes with unusual falling of HbA1c due to interference from dapsone treatment for leukocytoclastic vasculitis. He was a 52-year-old man, who was diagnosed with type 2 diabetes mellitus 5 years previously and who had been treated in our hospital in the past 3 years. Glycemia was controlled by sulfonylurea and metformin. During the 3-years follow-up period, HbA1c dropped significantly during the addition of dapsone treatment, although plasma glucose levels remained stable. HbA1c levels were raised after discontinuation of dapsone. With rechallenge of dapsone usage, HbA1c decreased again. We conclude that dapsone may be the cause of artificially low HbA1c. Other measurements to monitor glycemic control should be considered when dapsone is used for the treatment of concurrent disorders, such as autoimmune disease and pneumocystis jiroveci pneumonia.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan.
authors.forename: Ying-Chuen
authors.initials: YC
authors.lastname: Lai
authors.forename: Chou-Shiang
authors.initials: CS
authors.lastname: Wang
authors.forename: Yi-Ching
authors.initials: YC
authors.lastname: Wang
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Hsu
authors.forename: Lee-Ming
authors.initials: LM
authors.lastname: Chuang
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects* / Q000627:therapeutic use; D015415:Biomarkers / Q000378:metabolism; D003622:Dapsone / Q000009:adverse effects* / Q000627:therapeutic use; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000150:complications / Q000188:drug therapy*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D003622:Dapsone; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human