A Multicenter ICET-A Survey on Adherence to Annual Oral Glucose Tolerance Test (OGTT) Screening in Transfusion-Dependent Thalassemia (TDT) Patients - The Expert Clinicians’ Opinion on Factors Influencing the Adherence and on Alternative Strategies for Adherence Optimization

Background: Current guidelines for screening glucose dysregulation (GD) in patients with transfusion-dependent thalassemia (TDT) recommend an annual 2-hour oral glucose tolerance test (OGTT) starting at the age of 10 years. Objective: Assessment of adherence to OGTT screening in patients with TDT. Methods: A questionnaire was distributed to 18 Thalassemia Centers in 10 different countries, targeting factors influencing adherence to annual OGTT screening in specialized multidisciplinary pediatric and adult TDT units and identifying strategies to improve adherence to OGTT in TDT patients. Results: The mean reported percentage of all types of GD across 16 of the 18 centers at the last OGTT assessment was 32.0%, while the mean percentage for thalassemia-related diabetes mellitus (Th-RDM) was 12.2 ± 9.7% (range: 0% - 41%; median: 13.2 %) in all participating centers. Notably, a high percentage of suboptimal or poor adherence to annual OGTT screening (mean 41.3%; range 10-90%) was reported by 17/18 centers. Poor adherence to annual OGTT among eligible patients was multifactorial and related to both patients and the healthcare system barriers. The most commonly suggested actions by hematologists and endocrinologists for improving the adherence to OGTT were flexibility in timing, easy approach to test location, improved collaboration among team members, and persistent reminding. Conclusions: Young adult patients with TDT are at high risk for developing GD and Th-RDM. Thus, annual screening with a 2-hour OGTT is recommended. Nevertheless, several patient barriers are associated with low adherence to annual OGTT. It is desirable to develop intensive initiatives to improve the screening rate for GD, while studies are warranted to update the current guidelines in TDT patients with low-risk factors for GD and for countries with low-resource settings.