according a post hoc analysis of a large European database.
However, Ernesto Maddaloni, MD, of Sapienza University of Rome and University of Oxford (England), and colleagues noted that the risk is less than half that in patients with type 2 disease during the first several years after diagnosis but that, after 9 years, the risk curves cross over, and patients with latent autoimmune diabetes of adulthood (LADA) matriculate to a 25% greater risk microvascular complications than do their type 2 counterparts.
The results point to a need for tighter glycemic control in patients with latent autoimmune disease and “might have relevant implications for the understanding of the differential risk of complications between type 2 diabetes and autoimmune diabetes in general,” the researchers wrote online in The Lancet Diabetes & Endocrinology. They emphasized that the study represents the largest population of patients with latent autoimmune diabetes with the longest follow-up in a randomized controlled trial so far.
Diabetic microvascular complications are a major cause of end-stage renal disease and blindness in LADA, therefore, “implementing strict glycemic control from the time of diagnosis could reduce the later risk of microvascular complications in [these patients],” the authors wrote.
The researchers analyzed 30 years of data from the United Kingdom Prospective Diabetes Study, focusing on 564 patients with LADA and 4,464 adults with type 2 diabetes. The primary outcome was first occurrence of renal failure, death from renal disease, blindness in one eye, vitreous hemorrhage, or retinal laser treatment.
With a median follow-up of 17.3 years, 21% of all patients (1,041) developed microvascular complications, of which there were 65 renal events and 976 retinopathy events. Secondary outcomes were nephropathy and retinopathy.
The study measured incidence in 1,000 person-years and found that the incidence for the overall primary composite microvascular outcome was 5.3% for LADA and 10% for type 2 diabetes in the first 9 years after diagnosis (P = .0020), but 13.6% and 9.2%, respectively, after that (P less than .0001). That translated into adjusted hazard ratios of 0.45 for LADA, compared with type 2 diabetes, in the first 9 years (P less than .0001) and 1.25 beyond 9 years (P = .047). The incidence of retinopathy events was 5.3% for LADA and 9.6% for type 2 diabetes up to 9 years (P = .003), and 12.5% and 8.6% thereafter (P = .001). Nephropathy rates were similar in both groups at 1.3% or less.
“The lower risk of microvascular complications during the first years after the diagnosis of latent autoimmune diabetes needs further examination,” Dr. Maddaloni and colleagues wrote.
They cautioned that LADA is often misdiagnosed as a form of type 1 diabetes. “Therefore, latent autoimmune diabetes could be the right bench test for studying differences between autoimmune diabetes and type 2 diabetes, because of fewer disparities in age and disease duration than with the comparison of type 1 diabetes and type 2 diabetes,” they wrote.
In an accompanying editorial, Didac Mauricio, MD, of the Autonomous University of Barcelona, credited Dr. Maddaloni and colleagues with presenting evidence “of major relevance” in an adequately powered study that provided “a robust conclusion” about the risk of microvascular complications in latent autoimmune diabetes.
Dr. Mauricio noted that the study adds to the literature that different subgroups of type 2 diabetes patients exist and highlights the distinct characteristics of latent autoimmune diabetes. In addition, it builds on a previous study by Dr. Maddaloni and coauthors that found cardiovascular disease outcomes did not differ between latent autoimmune and type 2 diabetes (Diabetes Obes Metab. 2019;21:2115-22), he wrote. The research team’s most recent findings “emphasize the need for early identification of latent autoimmune disease,” he stated.
The findings also raise important questions about screening all patients for antibodies upon diagnosis of diabetes, he said. “I firmly believe that it is time to take action,” first, because antibody testing is likely cost-effective and cost-saving because it facilitates better-informed, more timely decisions early in the disease trajectory, and second, it has already been well documented that patients with latent autoimmune diabetes have a higher glycemic burden.
An alternative to early universal screening for antibodies would be to raise awareness, especially among general practitioners, about the importance of timely diagnosis of LADA, Dr. Mauricio added.
The study received funding from the European Foundation for the Study of Diabetes Mentorship Program, supported by AstraZeneca. Dr. Maddaloni disclosed financial relationships with Sanofi, Eli Lilly, Abbott, and AstraZeneca. Another author disclosed financial relationships with Boehringer Ingelheim, Merck, Bayer, AstraZeneca, Novartis, and Novo Nordisk. All the other authors had no relevant financial relationships to disclose. Dr. Mauricio disclosed financial relationships with AstraZeneca, Eli Lilly, Merck Sharp & Dohme, NovoNordisk, Sanofi, Almirall, Boehringer Ingelheim, Eli Lilly, Ferrer, Janssen, Menarini, and URGO.
SOURCE: Maddaloni E et al. Lancet Diabetes Endocrinol. 2020 Feb 4. doi: 0.1016/S2213-8587(20)30003-6.