Endocrine Abstracts

Introduction

Type 1 diabetes mellitus (T1DM) is an autoimmune disease in which pancreatic βcells are destroyed, generating an incapacity to maintain appropriate insulin and glucose concentration. On the other hand, type 2 diabetes mellitus (T2DM) is associated with varying degrees of insulin resistance (IR) and relative insulin deficiency. The association of T1DM and the clinical features of T2DM as obesity, hypertension, dyslipidemia, or metabolic syndrome (MS) is called “double-diabetes” and has been associated with an increased rate of chronic complications and cardiovascular diseases in patients with T1DM.

Case

A 46 years old female patient had had diabetes mellitus for 8 years, under premixed insulin (1.2 U/kg) and 2 g of metformin due to her glycemic imbalance (Hba1c: 14%) with a history of a few episodes of diabetic ketoacidosis (DKA), hypertension, weight gain under insulin, adult-onset diabetes in maternal grandfather, mother, brother, and sister. She was considered T2DM due to her clinical presentation that included a BMI of 30 kg/m², a waist circumference of 97 cm, acanthosis nigricans around her neck, and significant family history of diabetes. During her last hospitalization for glycemic imbalance, the biological assessment revealed positive antibodies to glutamic acid decarboxylase (GAD) over 2000 U/ml. The patient was diagnosed with T1DM and put under insulin in a basal/bolus regimen associated with 2 g of metformin to counter insulin resistance.

Discussion and conclusion

Double-diabetes (DD) was a term coined to describe individuals with type 1 diabetes showing clinical features compatible with type 2 diabetes. It has been variably used in literature, to describe both individuals with obesity and other insulin resistance (IR) characteristics. The mechanisms involved in the development of IR in patients with T1D remain unknown. Some studies have proposed that obesity due to a non-healthy lifestyle and over-insulinization in addition to the genetic background are its main cause. Meanwhile, others have reported that IR is present in patients with T1D even in the absence of obesity. Definition of a strict intermediate subtype between both types of diabetes is difficult, therefore this grey zone between them behaves more like a continuum according to current evidence.