Deteriorating diabetic control through adolescence - do the origins lie in childhood?

Aims To determine whether intra-individual measures of diabetes control deteriorated through adolescence and whether HbA(1c) in late childhood was predictive of HbA(1c) after adolescence. Methods Retrospective analysis of sequential 3-6 monthly data including HbA(1c), height, weight, and total daily insulin dosage in 118 patients with Type 1 diabetes aged between 8.00 and 17.99 years between 1983 and 1999. Results In females mean body mass index (BMI) increased sharply during adolescence but there was no significant increase in males. The mean total daily dose of insulin/weight (TDDI/W) increased sharply for females through puberty. Males exhibited a constant rate of increase in mean TDDI/W from pre- to post-puberty. There was a constant increase in mean HbA(1c) for females, with an estimated increase from pre- to post-puberty of 0.92%. In males there was only a slight increase from pre- to peri-puberty and no change subsequently. Comparing pre-puberty (8-9.99 years) and post-puberty (15-17.99 years) in the total group, 47% of patients remained in the same mean HbA(1c) grouping, 37% had worsened control and 16% had improved control. Analysis of change in the absolute value of mean HbA(1c) showed that the majority of patients had mean HbA(1c) values that remained within +/-1% (54%) or +/-2% (82%) from pre- to post-puberty. A significant proportion showed significantly worsening control with only a minority showing improved metabolic control from pre- to post-puberty. Conclusions The likelihood of a significant improvement in HbA(1c) from late childhood to adolescence is remote, with the majority of patients having either constant or deteriorating metabolic control.