Hypoglycemia: Incidence and Clinical Predictors in a Large Population-Based Sample of Children and Adolescents with IDDM

E A Davis; B Keating; G C Byrne; M Russell; T W Jones

doi:10.2337/diacare.20.1.22

Original Articles

Hypoglycemia: Incidence and Clinical Predictors in a Large Population-Based Sample of Children and Adolescents with IDDM

E A Davis, FRACP,
B Keating, BSC,
G C Byrne, FRACP,
M Russell, MN and
T W Jones, FRACP

Department of Diabetes and Endocrinology, Princess Margaret Hospital for Children Perth, Western Australia

Address correspondence and reprint requests to E.A. Davis, Diabetes Research Center, 501 Stemmler Hall, 36th and Hamilton Walk, Philadelphia, PA 19104-6015

Diabetes Care 1997 Jan; 20(1): 22-25. https://doi.org/10.2337/diacare.20.1.22

Abstract

OBJECTIVE To determine the frequency of moderate and severe hypoglycemia and to identify clinical predictors associated with its occurrence in a large population-based sample of children and adolescents with IDDM.

RESEARCH DESIGN AND METHODS A total of 657 patients (age: 12.1 ± 4.4 years, mean ± SD) were included in the study, yielding 1,449 patient-years of data. A prospective assessment of severe hypoglycemia (an event resulting in a seizure or coma) and moderate hypoglycemia (an event requiring assistance of another, excluding severe episodes) was made over a 3-year period. Patients and caregivers detailed episodes of significant hypoglycemia (moderate and severe events) and these were recorded at each 3-month clinic visit along with HbA_1c. Data were analyzed using generalized estimating equation models fitted with the exchange correlation structure.

RESULTS The overall incidence of severe events was 4.8/100 patient-years and of moderate events was 13.1/100 patient-years. Over 3 years, severe events occurred in 8.5% of children and moderate events occurred in 26.9%. Significant hypoglycemia was rare in the first 12 months after diagnosis. Rates of hypoglycemia were increased in children < 6 years of age versus > 6 years of age (40.9 vs. 16.6/100 patient-years, age ≤6 years vs. age > 6 years, P < 0.001). Rates of hypoglycemia doubled when HbA_1c fell below 8%, and children with HbA_1c < 7% had a threefold increase in both moderate and severe hypoglycemia (e.g., severe episodes 14.9 vs. 4.1/100 patient-years, HbA_1c ≤ 7% vs. HbA_1c > 7%, P < 0.001). Most severe events were seizures, and 75% of them occurred at night. The majority of events were related to missed meals or increased activity. However, in 38% no predisposing factor was evident.

CONCLUSIONS Newly diagnosed children appear to be protected from severe hypoglycemia. Rates increase with lower glycated hemoglobin, especially when mean HbA_1c is < 8.0%. Younger children, who may be more susceptible to the adverse effects of neuroglycopenia, are at a particular risk of significant hypoglycemia.