The incidence of severe hypoglycemia was determined in a 1-yr prospective study of 350 insulin-dependent diabetic (IDDM) children. There were no significant.
Ignacio Bergada, MD Samy Suissa, PhD Jackie Dufresne, RN Alicia Schiffrin, MD
Severe Hypoglycemia in IDDM Children
The incidence of severe hypoglycemia was determined in a 1-yr prospective study of 350 insulin-dependent diabetic (IDDM) children. There were no significant differences in mean glycosylated hemoglobin, age, and duration of disease between the patients who had severe hypoglycemia and those who did not. There were 25 episodes in 24 patients (6.8%). Their insulin doses at the time of the episode (U • kg"1 • day"1) were significantly higher than those of the nonhypoglycemic group (mean ± SD 1.01 ± 0.30 vs. 0.89 ± 0.29; P = .04). The hypoglycemic group had a significantly higher mean number of previous episodes of severe hypoglycemia than the nonhypoglycemic group (0.92 ± 1.18 vs. 0.25 ± 0.68; P = .01). In only 64% of the episodes, an unusual circumstance such as strenuous physical activity or missed or delayed meals preceded the event. Multivariate analysis of the data by logistic regression showed risks of developing hypoglycemia of 2.5 per 0.5 U/day insulin and of 2.0 per previous episode of severe hypoglycemia. We conclude that severe hypoglycemia may be a recurrent problem in some diabetic children, but it does not appear to be related to age or blood glucose control. The presence of previous episodes may be a guide to identify patients at greater risk of developing severe hypoglycemia. Adherence to regular testing, strict spacing and consistency of meals, and extra food for extra activity may reduce this serious complication. Diabetes Care 12:239-44, 1989
Glucose
1 mM = 18mg/dl
From the Diabetes Unit, Montreal Children's Hospital, McGill University Research Institute, and the Division of Clinical Epidemiology and Department of Epidemiology and Biostatistics, McGill University Montreal, Quebec, Canada. Address correspondence and reprint requests to A. Schiffrin, MD, Montreal Children's Hospital, McGill University Research Institute, Division of Endocrinology and Metabolism, 2300 Tupper Street, Montreal, Quebec H3H 1P3, Canada.
DIABETES CARE, VOL. 12, NO. 4, APRIL 1989
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evere hypoglycemia causing loss of consciousness or seizures, a serious complication of insulin therapy that potentially causes permanent neurologic sequelae, has been shown to occur in 4 26% of insulin-dependent diabetic (IDDM) patients ( 1 4). With the continuing application of intensified insulin therapy, the question has been raised about an increased risk of hypoglycemic episodes as a result of the efforts to achieve normoglycemia in patients with IDDM. Several studies have attempted to determine the relationship between blood glucose control and the incidence of severe hypoglycemia in IDDM patients (5-10). In most studies, glycosylated hemoglobin (HbA,) concentration and insulin dose (U • kg" 1 • day"1) were the factors used to assess the relationship. Goldstein et al. (4) reported that the risk of symptomatic hypoglycemia in a pediatric diabetic population treated conventionally increased as the HbA, concentration decreased. Casparie and Elving (2) found that diabetic patients treated with conventional therapy who developed severe hypoglycemia had a higher insulin dose than controls. Little is known about this severe complication in a large population of IDDM children treated with conventional therapy. The aim of our study was to determine the incidence and risk factors of severe hypoglycemia in a pediatric population of IDDM patients studied prospectively. With this purpose, we included only those episodes of severe unequivocal hypoglycemia that required outside assistance or caused loss of consciousness with or without seizures.
MATERIALS AND METHODS The clinic population studied consisted of 350 IDDM children aged 1.5-18 yr regularly followed at our insti239
SEVERE HYPOGLYCEMIA IN IDDM CHILDREN
tution at 3-mo intervals. In cases of poor control or severe social problems, patients were seen as often as once a week. Close follow-up was ensured by reminder phone calls before each clinic visit. All patients and their families received instruction in the management of their diabetes at the time of diagnosis by a physician, a nurse, and a dietitian. Most of the patients were treated with one or two daily injections of a mixture of short-acting and intermediate-acting insulin. One patient was on three to four insulin injections per day, and five patients were treated with continuous subcutaneous insulin-infusion (CSII) pumps. Patients were taught to adjust the short-acting insulin dose according to the blood glucose concentration before the insulin injection. Each patient received a balanced diet, which consisted of three meals and three snacks, following the recommendations of the Canadian Diabetes Association. Patients were encouraged to test their urinary ketones each morning and their blood glucose levels with reagent strips two or three times daily (before breakfast and supper and at bedtime). The aim of the treatment was to maintain blood glucose levels between 4.4 and 7 mM before breakfast and supper. In addition, they were instructed to increase their bedtime snack if their blood glucose at that time was
