Prevalence of intentional under- and overdosing of insulin in children and adolescents with type 1 diabetes

OBJECTIVE: The aim of this study was to evaluate the prevalence of insulin under- and overdosing in paediatric patients. RESEARCH DESIGN AND METHODS: Cross-sectional study including 241 patients (age 14.0 + 2.7 yr, 42.5% males) with type 1 diabetes from 21 diabetic outpatient clinics. Haemoglobin A1c (HbA1c), height, and weight were available from clinical records. Patients were interviewed with the Diabetes Self-Management Profile (DSMP) interview. T test, U test, and chi-squared test were used for comparison. RESULTS: On the basis of the DSMP, 103 (42.7%) patients (group A) showed adherence to the therapeutic insulin regimen, while 71 (29.5%) patients (group B) confessed intentional over and/or under-dosing of insulin. Sixty-seven (27.8%) adolescents (group C) reported management problems leading to unintended inappropriate insulin dosages. In group B, 55 (22.8%) injected higher insulin doses and 58 (24.1%) omitted insulin. Patients of group B compared to group A were older 15.0 (±2.5) vs. 14.0 (±2.5) yr (p < 0.01), older at onset 9.5 (±3.6) vs. 8.3 (±3.8) yr (p = 0.05), were more often girls (69 vs. 45.6%), had a higher actual HbA1c (8.7 ± 1.7 vs. 7.8 ± 1.2%), and a higher average HbA1c in the previous year (8.3 ± 1.6 vs. 7.9 ± 1.2%) (p < 0.01). No significant differences could be found between group A and group C. CONCLUSION: Intentional overdosing of insulin is almost as prevalent in children and adolescents as insulin omission. Females are more at risk.