From the Guidelines
For a patient with suspected Latent Autoimmune Diabetes in Adults (LADA), the recommended workup includes measuring titres of islet-associated autoantibodies, such as anti-GAD, to aid in identification and encourage a more rapid transition to insulin therapy. The workup for LADA should prioritize autoantibody testing, specifically for GAD65 antibodies, which are present in most LADA cases, as suggested by the American Diabetes Association and the European Association for the Study of Diabetes 1. Some key steps in the workup include:
- Conducting a fasting plasma glucose test and HbA1c to assess blood sugar levels
- Performing autoantibody testing, specifically for GAD65 antibodies
- Measuring C-peptide levels to evaluate residual beta-cell function, although this should be done with caution and consideration of the patient's insulin treatment status, as outlined in the 2024 standards of care in diabetes 1
- Considering genetic testing for HLA-DQB10302 and HLA-DRB104, which are associated with LADA The most recent guidelines from 2024 suggest a flowchart for investigation of suspected type 1 diabetes in newly diagnosed adults, which may be applicable to LADA patients as well 1. However, the primary focus should be on identifying autoantibodies and evaluating beta-cell function to distinguish LADA from Type 2 diabetes and allow for appropriate management. Early identification of LADA is crucial, as these patients may require insulin therapy sooner to preserve beta-cell function and prevent complications, and initiating insulin therapy earlier than in typical Type 2 diabetes is often necessary. Lifestyle modifications and metformin may be considered initially, but close monitoring of blood glucose levels is essential to determine the need for insulin therapy 1.
From the Research
Diagnostic Criteria for LADA
The workup for a patient with Latent Autoimmune Diabetes in Adults (LADA) involves several diagnostic criteria, including:
- Age of onset: 20-48 years old 2
- Presence of autoimmune antibodies, such as glutamic acid decarboxylase (GAD) antibodies 2
- Fasting plasma glucose levels: > or = 16.5 mmol/L (297 mg/dl) 2
- C-peptide levels: low and flat curve (0.4,0.8 and 0.8 nmol/L respectively) 2
- Body mass index (BMI): < or = 25 2
- Presence of HLA-DQ beta chain substitution of aspartate molecule at position 57 (susceptible gene) 2
Diagnostic Tests
Diagnostic tests for LADA include:
- Mixed Meal Tolerance Test 3
- i.v. Glucagon Stimulation Test 3
- Measurement of GAD antibodies 3, 2
- Measurement of C-peptide levels 2, 4
- Measurement of HbA1c levels 5, 4
Treatment Approach
The treatment approach for LADA involves:
- Early insulin treatment to maintain metabolic control and prevent further destruction of residual islet B cells 5, 2
- Dietary and exercise habits to achieve tight metabolic control 5, 4
- Consideration of intra-lymphatic GAD-alum treatment to preserve beta cell function 3
- Avoidance of sulphonylurea (SU) as a first-line treatment due to the risk of earlier insulin dependence 6