Recognizing and Appropriately Treating Latent Autoimmune Diabetes in Adults
Latent autoimmune diabetes in adults (LADA) is considered a subgroup of type 1 diabetes and is often misdiagnosed because of a lack of both awareness and standardized diagnostic criteria (1–3). LADA is characterized by adult-onset diabetes and circulating autoimmune antibodies; thus, patients may present clinically with characteristics of both type 1 and type 2 diabetes (2–5). Typically, the clinical features of type 1 diabetes seen in LADA include a lower BMI compared to what is typical in type 2 diabetes and autoimmunity against one or more of the following antibodies: islet cell autoantibodies (ICA), autoantibodies to glutamic acid decarboxylase (GAD), tyrosine phosphatase–related islet antigen 2 (IA-2), and insulin autoantibodies (IAA) (4,5). The characteristics of type 2 diabetes that may present in LADA include older age at onset and insulin resistance or deficiency. Characteristics of LADA tend to include an intermediate level of β-cell dysfunction between those in type 1 and type 2 diabetes, faster decline of C-peptide compared to type 2 diabetes, and a level of insulin resistance that is comparable to type 1 diabetes (4). β-Cell decline is variable in LADA, as measured by C-peptide levels (5–7).
Although it has a closer pathophysiological relationship to type 1 diabetes, LADA is often misdiagnosed and treated as type 2 diabetes (2–5). This results in insufficient glycemic control and harm to patients. It is imperative to establish distinct practice guidelines for the diagnosis and treatment of LADA and for providers to recognize this clinical scenario as one that requires special testing to establish a proper diagnosis and thus improve patient safety and treatment efficacy.
The similarities between type 1 diabetes, type 2 diabetes, and LADA can make diagnosis difficult (Table 1). There are, however, other characteristics for this population that may …