Time to Insulin Initiation Cannot Be Used in Defining Latent Autoimmune Diabetes in Adults

OBJECTIVE—Latent autoimmune diabetes in adults is type 1 diabetes presenting as non–insulin dependent diabetes. One feature of the selection criteria is time independent of insulin treatment. We examine the validity of this criterion. RESEARCH DESIGN AND METHODS—Patients were recruited in nine European centers, and clinicians reported on criteria for initiating insulin. All patients were tested for GAD antibodies (GADAs) in a central laboratory. We examined time to insulin treatment for GADA-positive patients in six participating centers. RESULTS—There was intercenter variation in the criteria used to initiate insulin. Median time to insulin was 16.15 months (interqartile range 6.7–25.5) in centers with GADA testing compared with 45.6 months (29.5–61.8) in centers without routine GADA testing (P < 0.002). CONCLUSION—Time to insulin should not be used to define patients with LADA because it is dependent on local clinical judgment and the use of laboratory tests for GADA.