New classification of diabetes mellitus 2018

In 2018, the American Diabetes Association (ADA) and the World Health Organization (WHO) updated the classification and diagnosis of diabetes mellitus. The new classification system is based on the 2018 International Expert Committee Report on the Diagnosis and Classification of Diabetes Mellitus.

Here are the key changes:

New Classification Categories:

  1. Type 1 Diabetes (T1D): Autoimmune diabetes that typically develops in childhood or adolescence, characterized by a complete lack of insulin production.
  2. Type 2 Diabetes (T2D): Non-autoimmune diabetes that typically develops in adulthood, characterized by insulin resistance and impaired insulin secretion.
  3. Gestational Diabetes Mellitus (GDM): Diabetes that develops during pregnancy, typically in the second or third trimester.
  4. LADA (Latent Autoimmune Diabetes in Adults): A form of autoimmune diabetes that develops in adults, characterized by a slow progression to insulin deficiency.
  5. MODY (Maturity-Onset Diabetes of the Young): A rare form of diabetes caused by mutations in specific genes, typically presenting in young adulthood.
  6. Secondary Diabetes: Diabetes that develops as a result of another disease or condition, such as pancreatitis, pancreatic surgery, or certain medications.

New Diagnostic Criteria:

  1. Fasting Plasma Glucose (FPG): ≥ 7.0 mmol/L (126 mg/dL) or
  2. Oral Glucose Tolerance Test (OGTT): ≥ 11.1 mmol/L (200 mg/dL) at 2 hours
  3. Hemoglobin A1c (HbA1c): ≥ 6.5%

Additional Criteria:

  1. Random Plasma Glucose: ≥ 11.1 mmol/L (200 mg/dL) in the presence of symptoms of hyperglycemia (e.g., polyuria, polydipsia, blurred vision)
  2. Genetic Testing: May be used to confirm a diagnosis of MODY or LADA

Key Changes:

  1. The term "Impaired Fasting Glucose" (IFG) has been replaced with "Prediabetes," which is defined as a FPG of 5.6-6.9 mmol/L (100-125 mg/dL) or an OGTT of 7.8-11.0 mmol/L (140-198 mg/dL) at 2 hours.
  2. The term "Impaired Glucose Tolerance" (IGT) has been replaced with "Prediabetes," which is defined as an OGTT of 7.8-11.0 mmol/L (140-198 mg/dL) at 2 hours.
  3. The ADA and WHO no longer use the term "mild" or "severe" to describe diabetes, as these terms are not well-defined and can be misleading.

These changes aim to provide a more accurate and consistent classification and diagnosis of diabetes mellitus, which can help improve patient care and outcomes.