International comparison of glycaemic control in people with type 1 diabetes: an update and extension

Abstract

Aims: To update and extend a previous cross-sectional international comparison of glycaemic control in people with type 1 diabetes. Methods: Data were obtained for 520,392 children and adults with type 1 diabetes from 17 population and five clinic-based data sources in countries or regions between 2016 and 2020. Median HbA1c(IQR) and proportions of individuals with HbA1c<58mmol/mol (<7.5%), 58 – 74 mmol/mol (7.5 – 8.9%) and ≥ 75 mmol/mol (≥ 9.0%) were compared between populations for individuals aged <15, 15 – 24 and ≥ 25years. Logistic regression was used to estimate the odds ratio (OR) of HbA1c< 58 mmol/mol (< 7.5%) relative to ≥ 58 mmol/mol (≥ 7.5%), stratified and adjusted for sex, age, and data source. Where possible, changes in the proportion of individuals in each HbA1c category compared to previous estimates were calculated. Results: Median HbA1c varied from 55 to 79 mmol/mol (7.2 to 9.4%) across data sources and age groups so a pooled estimate was deemed inappropriate. OR (95% CI) for HbA1c< 58 mmol/mol (<7.5 %) were 0.91 (0.90 – 0.92) for women compared to men, 1.68 (1.65 – 1.71) for people aged < 15 years and 0.81 (0.79 – 0.82) aged15 – 24 years compared to those aged ≥ 25 years. Differences between populations persisted after adjusting for sex, age, and data source. In general, compared to our previous analysis, the proportion of people with an HbA1c<58 mmol/l (<7.5%) increased and proportions of people with HbA1c≥ 75 mmol/mol (≥ 9.0%) decreased. Conclusions: Glycaemic control of type 1 diabetes continues to vary substantially between age groups and data sources. While some improvement over time has been observed, glycaemic control remains sub-optimal for most people with Type 1 diabetes.