LADA refers to Latent Autoimmune Diabetes in Adults. Other names for this type of diabetes are:

• Latent type 1 diabetes
• Slowly progressive Insulin Dependent Diabetes Mellitus (SPIDDM)
• Slowly progressive type 1 diabetes
• Type 1 1/2 diabetes (One and a half)
• and Autoimmune diabetes in adults with slowly progressive beta-cell failure (ADASP).

It is also known as 1 1/2 (One and a half) diabetes mellitus because it shares features of both type 1 and type2 diabetes mellitus. It is a heterogeneous disease. It is responsible for 2- 12% of adult-onset diabetes mellitus, and prevalence varies in different populations. Patients with LADA present after 30 years with type 2 diabetes features and get treated with oral antidiabetic agents. They will rapidly become unresponsive to oral antidiabetic agents and will need insulin to control their blood sugars. They will also show positivity for antibodies against pancreatic beta cells (GAD, IA2, ZnT8, or insulin antibody). The diagnosis of LADA is suspected in patients with diabetes having:

• Age of onset > 30 years
• Presence of any islet antibody and
• Absence of insulin requirement for at least six months from diagnosis

As compared to type 1 diabetes mellitus, LADA is a mild form of autoimmune diabetes with gradual onset and slow progression. It is evidenced by the c-peptide level (a marker of residual β-cell function), which declines slowly in LADA compared to type 1 diabetes. Hence the acute complications like diabetic ketoacidosis are less common in LADA than type 1 diabetes mellitus. But there is autoantibody and T cell-mediated destruction of the pancreas' beta cells, ultimately leading to insulin deficiency as in type 1 diabetes mellitus, which necessitates treatment with insulin. It has features of type 2 diabetes mellitus with the age of onset for more than 30 years. It has a slow onset, no significant weight loss, polyuria, or acute complications like diabetic ketoacidosis. Patients have varying degrees of insulin resistance and respond initially to oral antidiabetic agents. But as compared to type 2 diabetes, LADA patients become unresponsive to oral antidiabetic drugs rapidly (generally six months to 2 years) and become insulin-dependent. Moreover, compared to type 2 diabetes mellitus, LADA generally has no family history of diabetes or feature of metabolic syndrome (hypertension, obesity, or dyslipidemia).