COVID-19 Vaccine-Induced Rapid Progression of Prediabetes to Ketosis-Prone Diabetes Mellitus in an Elderly Male

Studies show a low progression rate of prediabetes to Type 2 diabetes mellitus (DM) that we commonly seek to reverse, but we don’t associate prediabetes as a lead-up to the first presentation of ketosis. We present a prediabetic who, in less than a year, converted to GAD65 antibody-positive diabetes mellitus with a diabetic ketoacidosis presentation. A 69-year-old male presented with three weeks of fatigue, polyuria, polydipsia, abdominal pain, and weight loss. Vital signs and physical exam were normal except for abdominal tenderness and dry oral mucosa. Complete blood count (CBC) was normal; blood glucose was severely elevated with mild corrected hyponatremia; elevated anion gap metabolic acidosis with glucosuria and ketonuria. He received an insulin drip, normal saline, and potassium in the intensive care unit. His anion gap closed overnight and was switched to basal-bolus insulin. Hemoglobin A1c (HbA1c) came out to be higher than expected as compared to last year of low prediabetic value, decreased c-peptide levels, and positive anti-GAD65 antibody. His first abnormal HbA1c was 5.8% a year ago and no autoimmune marker was checked before. He was vaccinated with the messenger ribonucleic acid (mRNA) coronavirus disease 2019 (COVID-19) vaccine a year ago with an mRNA vaccine booster two months earlier. He was not COVID-19 infected. We discharged him with a basal-bolus insulin regimen. Type I DM passes from autoimmunity-positive normoglycemia to dysglycemia to the symptomatic stage, typically progressing more rapidly in children than in older adults. A new Type I or dysglycemia in Type II DM is increasingly reported after COVID-19 vaccines/infection. Mechanisms could be cytokine-mediated beta-cell damage or autoimmunity after mRNA vaccines or as a part of autoimmune syndrome induced by vaccine adjuvants. This case reports the rapid progression of prediabetes to Type 1 rather than Type 2 DM and highlights the possibility of dysglycemia after COVID-19 vaccines and calls for measures to prevent or early management of these side effects.