Prevalence of latent and overt polyautoimmunity in type 1 diabetes: A systematic review and meta-analysis

Background: Patients afflicted by type 1 diabetes (T1D) exhibit polyautoimmunity (PolyA). However, the frequency and distribution of PolyA in T1D is still unknown. Objective: We conducted a systematic review and meta-analysis to define the prevalence of latent and overt PolyA in individuals with T1D. Methods: Following PRISMA guidelines, a comprehensive search across medical databases identified studies on latent and overt PolyA in T1D. Two researchers independently screened, extracted data, and assessed study quality. A random effects model was utilized to calculate the pooled prevalence, along with its corresponding 95 % confidence interval (CI), for latent PolyA and overt PolyA. Meta-regression analysis was conducted to study the effect of study designs, age, sex, and duration of disease on pooled prevalence. Results: A total of 158 articles, encompassing a diverse composition of study designs were scrutinized. The analysis included 270,890 individuals with a confirmed diagnosis of T1D. The gender was evenly distributed (50.30 % male). Notably, our analysis unveiled an overt PolyA prevalence rate of 8.50 % (95 % CI, 6.77 to 10.62), with North America having the highest rates (14.50 %, 95 % CI, 7.58 to 24.89). This PolyA profile was further characterized by a substantial incidence of concurrent autoimmune thyroid disease (7.44 %, 95 % CI, 5.65 to 9.74). Moreover, we identified a notable prevalence of latent PolyA in the T1D population, quantified at 14.45 % (95 % CI, 11.17 to 18.49) being most frequent in Asia (23.29 %, 95 % CI, 16.29 to 32.15) and Oceania (21.53 %, 95 % CI, 16.48 to 27.62). Remarkably, this latent PolyA phenomenon primarily featured an array of autoantibodies, including rheumatoid factor, followed by Ro52, thyroid peroxidase antibodies, and thyroglobulin antibodies. Duration of the disease was associated with a highest frequency of latent (β: 0.0456, P-value: 0.0140) and overt PolyA (β: 0.0373, P-value: 0.0152). No difference in the pooled prevalence by study design was observed. Conclusion: This meta-analysis constitutes a substantial advancement in the realm of early detection of PolyA in the context of T1D. Individuals with T1D should regularly undergo assessments to identify potential concurrent autoimmune diseases, especially as they age.