[Nocturnal hypoglycemia in type-I diabetics, an underestimated risk?]

In 22 type I labile diabetics aged 20-64 years, various nighttime blood sugar (BS) values were obtained. Although 13 patients in 15 of 43 nights investigated measured below 2.8 mmol/l (50 mg%) for many hours, two thirds remained symptomless while the remainder suffered from minor hypoglycemic symptoms. The lowest BS values were obtained at about 3 a.m. Prospective as well as retrospective estimation of the hypoglycemic risk was performed with the aid of fasting and bed time BS. Causes and measures for prevention of the unexpectedly large number of episodes of nighttime hypoglycemia are discussed. Additionally, 18 healthy volunteers aged 24-61 years were investigated during 22 nights in regard to BS-values for comparative purposes: the lowest measured BS was 3.7 mmol/l (66 mg%) with an average nighttime BS of 4.9 +/- 1.1 mmol/l (86 +/- 5 mg%).