Assessing the uptake of the type 1 diabetes core outcome set in randomized controlled trials: A Cross-Sectional study

Aims: This study analyzed uptake of the core outcome set (COS) for type 1 diabetes (T1D) and trends in its use before and after its development in December 2017. Methods: On June 26, 2023, ClinicalTrials.gov was systematically searched for T1D randomized controlled trials. The Core Outcome Measures in Effectiveness Trials (COMET) database provided a COS of eight key outcomes for analysis. Included trials were analyzed for COS uptake before and after its release in December 2017 in a masked, duplicate fashion by independent reviewers. We also calculated the proportion of trials that measured the complete COS and assessed the most frequently reported COS outcomes. Results: Of 3,792 originally screened articles, 144 RCTs were included in the final sample. Following COS publication, its use steadily decreased. Within the COS, HbA1c and severe hypoglycemia were most frequently implemented as endpoints; other recommended outcomes were rarely used in the published trials. Conclusion: Despite the 2017 T1D COS publication, use has decreased over time. This inconsistency negatively influences evidence-based practices and care. Educating researchers on COS and promoting uptake is crucial. Wider COS adoption in T1D trials could enhance clinical research overall. Further study of barriers and facilitators influencing uptake is essential to support consistent use and reporting.