Association between HbA and the development of cystic fibrosis-related diabetes.

Aims: To examine HbA as a predictor of risk for future development of cystic fibrosis-related diabetes and to assess the association with the development of retinopathy in people with cystic fibrosis-related diabetes.

Methods: A 7-year retrospective longitudinal study was conducted in 50 adults with cystic fibrosis, comparing oral glucose tolerance test results with HbA values in predicting the development of cystic fibrosis-related diabetes. Retinal screening data were also compared with HbA measurements to assess microvascular outcome.

Results: An HbA value ≥37 mmol/mol (5.5%; hazard ratio 3.49, CI 1.5-8.1) was significantly associated with the development of dysglycaemia, as defined by the oral glucose tolerance test over a 7-year period. Severity of diabetic retinopathy was associated with a higher HbA and longer duration of cystic fibrosis-related diabetes.

Conclusion: There is a link between HbA level and the future development of dysglycaemia in cystic fibrosis based on oral glucose tolerance test, as well as microvascular outcomes. Although current guidance does not advocate the use of HbA as a diagnostic tool in cystic fibrosis-related diabetes, it may be of clinical use in determining individuals at risk of future development of cystic fibrosis-related diabetes.