Risk factors of severe hypoglycaemia in adult patients with Type I diabetes -: a prospective population based study

The objective of this study was to identify possible risk factors of severe hypoglycaemia (SW) in a prospective population based study of adult Type I (insulin-dependent) diabetic patients. A representative sample of 684 patients (41% women, mean +/- SD age 36 +/- II, diabetes duration 18 +/- II years), living in the district of Northrhine (9.5 million inhabitants), Germany, were examined in their homes using a mobile ambulance. A comprehensive baseline assessment of possible predictors of SH included sociodemographic and disease related variables, hypoglycaemia awareness, diabetes management, and attitudes and behavioural aspects as expressed by the patients. After a mean of 19 +/- 6 months 669 (98%) patients were interviewed about events of SH since the baseline examination. Using the multiple Cox proportional hazards model, five risk factors of SH were identified: SI-I during the preceding year [hazard ratio (I IR) 2.7, 95% confidence intervals (CI) 1.8-4.2], any history of SII (IIR 1.9, CI 1.1-3.4), C-peptide negativity (HR 4.0, CI 1.2-12.7), social status (WR 0.8 for a difference of 5 units for a value range of 0-24, CI 0.6-0.9), and patients' determination to reach normoglycaemia (HR 0.7 for a difference of 1 unit for a value range of 1-6, CI 0.5-0.9), indicating that the lower the social status and the higher the patients' determination to reach normoglycaemia, the higher the risk of SI-I. After eliminating the history of hypoglycaemia from the model, impaired hypoglycaemia awareness and patients' inappropriate denial of SW as their particular problem became additional significant risk factors of SII. In conclusion, in this population based study of adult Spe I diabetic patients, C-peptide negativity, a previous event of SI-I, patients' determination to reach normoglycaemia and social class were risk factors of SH.