Meta-Analysis: Global Prevalence of Coeliac Disease in Type 1 Diabetes.

Background: Coeliac disease (CD) is common in patients with type 1 diabetes (T1D), but prevalence varies globally due to differing screening protocols. There have been substantial changes in screening guidelines over the past two decades.

Aim: To evaluate CD prevalence in patients with T1D, focusing on screening studies using antitissue transglutaminase (anti-tTG) antibody.

Methods: We searched PubMed, Web of Science, Embase and Scopus for studies published up to 11 December 2023 using keywords related to CD and diabetes. We used random-effects models for overall prevalence and all subgroups, with heterogeneity assessed using Cochran's Q test and the I² statistic performed in STATA 18.

Results: We included 106 articles involving 65,102 T1D patients across 40 countries. The pooled CD seroprevalence and confirmed CD prevalence were 9% (95% confidence interval, CI, 8%-10%) and 6% (95% CI 5%-7%), respectively. The prevalence was higher in females and children. Denmark, Saudi Arabia and Libya exhibited the highest prevalence (11%), followed by India and Egypt (10%). Belgium, France, Germany, South Africa and the United States had the lowest prevalence (2%). High-income countries showed significantly a lower CD prevalence than middle-income countries (p = 0.03). Meta-regression based on the Human Development Index (HDI) indicated that countries with higher HDI have lower seroprevalence and confirmed CD prevalence.

Conclusion: Approximately 1 in 16 patients globally and 1 in 12 patients in Asia and the Middle East with T1D has CD. We suggest that all patients with T1D should be screened for CD.