Hypoglycaemia symptoms and impaired awareness of hypoglycaemia in adults with Type 1 diabetes: the association with diabetes duration

AIMS: To examine the association between diabetes duration and hypoglycaemia symptom profiles and the presence of impaired awareness of hypoglycaemia. METHODS: A cross-sectional study was performed, using validated methods for recording hypoglycaemia symptoms and assessing hypoglycaemia awareness. The associations between symptom intensity, hypoglycaemia awareness and diabetes duration were examined, and the prevalence of impaired awareness was ascertained for Type 1 diabetes of differing durations. RESULTS: Questionnaires were mailed to 636 adults with Type 1 diabetes, of whom 445 (70%) returned them. A total of 440 completed questionnaires were suitable for analysis. Longer diabetes duration was associated with lower intensity of autonomic symptoms (P for trend <0.001), but no association was observed with neuroglycopenic symptoms. The overall prevalence of impaired awareness of hypoglycaemia in this cohort was 17% (95% CI 14-21%) and increased with diabetes duration, from 3% for duration 2-9 years to 28% for duration ≥30 years (P for trend <0.001). Low autonomic symptom scores were not associated with a higher prevalence of impaired awareness. CONCLUSIONS: Longer diabetes duration was associated with lower intensity of autonomic symptoms and a higher prevalence of impaired awareness of hypoglycaemia, suggesting that subjective symptoms of hypoglycaemia change over time. These observations underline the need for regular patient education about hypoglycaemia symptomatology and clinical screening for impaired awareness of hypoglycaemia.