Prevalence and Identification of Type 1 Diabetes in Chinese Adults with Newly-Diagnosed Diabetes

Background: The incidence of type 1 diabetes mellitus (T1DM), especially in children, has rapidly increased in China. However, the prevalence of adult-onset classic T1DM and latent autoimmune diabetes of adults (LADA) remains unknown. Methods: A nationwide, multicenter survey of newly-diagnosed diabetes in adults aged ≥30 years was conducted from hospitals in 24 Chinese provincial administrative areas from April 2015 to October 2017. Classic T1DM, identified based on insulin-dependency, and standardized glutamic acid decarboxylase autoantibody testing, was used to differentiate LADA from patients with initially an undefined diabetes type. The age and sex distributions from a large national survey of diabetes in China conducted in 2010, were used to standardize the prevalence of T1DM and LADA. Findings: Among 17,349 adult patients, the prevalence of T1DM was 5·84% (5·14% in males and 6·16% in females), with 65% of these having LADA. The prevalence of classic T1DM decreased with increasing age (p 0·05). The prevalence of T1DM in overweight or obese patients was 3·4% and 2·4%, respectively, and LADA accounted for 75% and 80% of T1DM in these two groups. LADA's cumulative age distribution was much closer to type 2 diabetes mellitus (T2DM) than to that of classic T1DM. Interpretation: T1DM, especially LADA, was prevalent in newly-diagnosed adult-onset diabetes in China, which highlights the importance of identification of LADA in clinical practice in China. Funding Statement: The National Science and Technology Infrastructure Program and the National Key R&D Program of China. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: The ethics review committee/institutional review board of each of the participating hospitals approved the study protocol. Written informed consent was obtained from all the participants before data collection.