Prevalence and risk factors for impaired awareness of hypoglycaemia: A registry-based study of 10,202 adults with type 1 diabetes in Norway.

Aims: The aim of this study is to determine the prevalence of impaired awareness of hypoglycaemia (IAH) and examine risk factors for IAH in adults with type 1 diabetes.

Methods: We conducted a population-based registry study of 10,202 adults (≥18 years) with type 1 diabetes using data from the Norwegian Diabetes Register for Adults. The registry used the 1-item Gold scale, measuring hypoglycaemia symptom awareness. We calculated the overall prevalence of IAH (Gold score ≥4) (95% CI) and prevalence for subgroups based on demographic and clinical variables. We estimated IAH prevalence based on continuous scales of age, diabetes duration and HbA using predicted probabilities from generalised additive logistic regression models. Finally, we quantified the associations of selected variables on IAH prevalence using log-binomial regression models.

Results: Overall, 18.0% reported IAH (95% CI 17.2, 18.7). The prevalence increased linearly with the participants' age, whereas the associations of diabetes duration and HbA with IAH were non-linear with higher prevalence in both lower and higher tails of their distributions. Multiple severe hypoglycaemic events, female sex, age ≥ 65 years, diabetes duration ≤4 years or ≥ 30 years, multiple DKA events and CGM use were associated with higher risk for IAH. HbA 65-74 mmol/mol (8.1-8.9%) was associated with lower risk for IAH.

Conclusions: In this nationwide study, the IAH prevalence was 18.0%. Multiple hypoglycaemic events, female sex and diabetes duration were identified as important risk factors for IAH. Study findings highlight the complexity of self-reported hypoglycaemia symptom awareness and emphasise the importance of routinely addressing symptom awareness in diabetes follow-up.