A repeated cross-sectional survey of severe hypoglycaemia in 178 Type 1 diabetes mellitus patients performed in 1984 and 1998

Aims To study the prevalence of severe hypoglycaemia (SH) in relation to risk factors in Type 1 diabetic (T1 DM) patients over a period of 14 years. Methods We performed a cross-sectional survey of a cohort of 178 T1 DM patients registered at our out-patient clinic in 1984 to be repeated in 1998. An identical questionnaire was sent to the patients in the beginning of 1985 and 1999, respectively, regarding the problem of SH in the preceding year. Additional clinical data were obtained from the patients' medical records on insulin treatment, long-term complications, morbidity, and co-medication. Results At follow up, the use of multiple insulin injection therapy had increased from 71% to 98% (P<0.001) and daily self-monitoring of blood glucose (SMBG) from 17% to 48% (P<0.001). Twenty-seven percent were treated with direct-acting insulin analogues in 1998. An increasing number of patients reported unawareness of hypoglycaemia, 54% vs. 40% (P<0.01), and nocturnal events were more frequent, 83% vs. 76% (P<0.05). The prevalence of SH had increased from 17% to 27% (P<0.05) and a slight decrease of HbA(1c) , 7.6% to 7.4% (P<0.05) was documented. Conclusions We conclude that despite more frequent use of multiple injection therapy and SMBG, the prevalence of SH has increased by >50% over 14 years. A multiple logistic regression analysis of risk factors for SH explained less than 10% of the variance, implicating only unawareness of hypoglycaemia and HbA(1c) .