In latent autoimmune diabetes in adults, mortality was similar to T2DM but retinopathy was higher at 5.9 y
If confirmed, the findings of different disease trajectories among patients with latent autoimmune diabetes in adults could eventually merit reclassification of the types of diabetes, an ACP Journal Club commentary said.
A population-based study compared outcomes between Swedish patients with newly diagnosed latent autoimmune diabetes in adults (LADA), type 2 diabetes, adult-onset type 1 diabetes, or no diabetes. Mortality was higher with LADA, type 1, or type 2 diabetes compared to control subjects. The incidence of cardiovascular disease was elevated in patients with LADA and high levels of auto immunity, but not those with LADA and low levels. LADA patients also had higher HbA1c levels than the other studied groups.
The study was published by Diabetes Care on Aug. 28, 2023. The following commentary by Caoimhe Casey, MB, and Sean F. Dinneen, MD, was published in the ACP Journal Club section of Annals of Internal Medicine on Jan. 2.
Classification of diabetes into type 1, type 2, and other specific types is crude and based mainly on age and metabolic phenotype at presentation. Classification based on future risk for adverse outcomes would be preferable for clinicians, allowing targeting of therapy in a personalized medicine approach. The study by Wei and colleagues is remarkable in that it used real-world (registry) data to phenotype a large cohort of patients with newly diagnosed diabetes and compared them with a random sample of population controls for development of hard end points including death, cardiovascular disease (CVD), retinopathy, and nephropathy. Using baseline measures of GADA and C-peptide levels, patients with diabetes were classified into 4 categories (type 1, type 2, and LADA high or LADA low based on GADA levels above or below the median at diagnosis) and followed up for up to 10 years, with complications documented through use of existing Swedish national data sets.
Some findings align with what a practicing clinician might expect. For example, more patients with LADA (both high and low subgroups) than with type 2 diabetes were using insulin therapy within 6 months of diagnosis, and most types of diabetes were associated with higher mortality rates than the control population. Where the study deviates from expectations is in the lower rates of all-cause mortality in the LADA-high subgroup, with rates similar to controls, and CVD risks for type 1 diabetes and the LADA-low subgroup that were similar to controls. However, these observations should be interpreted with caution because the LADA group had relatively few events (35 incident CVD events and 49 deaths). Perhaps the most interesting observations are for microvascular complications, with a clear separation in the incidence curves for retinopathy (higher in the LADA vs. type 2 diabetes group) and a trend toward higher nephropathy risk in the type 2 diabetes group.
Given the observational nature of the study and low event rates for some outcomes, the reported findings are unlikely to influence clinical practice in the short term. Nevertheless, the results provide a signpost for the future, with profiling of patients with newly diagnosed diabetes (to include GADA status) to predict disease trajectories. Other groups have taken a similar approach, and if the body of evidence grows, then it may be time to reconsider the current classification of diabetes.