[What glycemic control can be achieved in young diabetics without residual secretion of endogenous insulin? What is the frequency of severe hypoglycemia and subclinical complications?].

BACKGROUND

Successful therapeutic management of the child and adolescent with diabetes mellitus requires insulin administration, dietary management, physical activity and physical fitness, and emotional support. The ultimate aim is to avoid long-term microvascular, renal and neurologic complications by maintaining blood glucose concentrations close to the normal range. We determined the mean annual glycosylated hemoglobin levels (HbA1c) that can be achieved in young diabetic patients without residual insulin secretion.

POPULATION AND METHODS

One hundred and twenty-nine patients aged 17.7 +/- 6.4 yr (m +/- SD) were followed sequentially for 1 year by the same pediatric diebetologist. They had a diabetes duration from 2 to 27 yr (mean: 9.7). Mean age at onset of diabetes was 8.1 +/- 3.7 yr. C-peptide was undetectable in all patients. Subclinical retinopathy, neuropathy and nephropathy were looked for in all patients. HbA1c was measured by an HPLC method (normal range: 4.4-6.0%) at each visit (6.6 +/- 1.9 visits/yr/patient).

RESULTS

Mean (SD) annual HbA1c levels were 6.9 +/- 1.5%, ie 115% of normal values. The frequency of monthly home blood glucose monitoring (HBGM) was between 0 and 250 measurements (77 +/- 49). HbA1c was not related to sex, ethnicity, age, and duration of diabetes. There was no difference between the 84 patients on only two or three daily insulin injections (aged 15.1 +/- 5.6 yr with a diabetes duration of 7.5 +/- 5.2 yr), and the 45 patients on four injections using the basal bolus regimen (aged 22.5 +/- 5.2 yr with a diabetes duration of 13.7 +/- 5.5 yr). The regression analysis showed a weak but significant inverse correlation between HbA1c and frequency of HBGM as well as frequency of outpatient clinic attendance. The yearly incidence rates of severe hypoglycemia were 0.10 in the two injection group and 0.31 in the four injection group without relationship to HbA1c levels. Frequency of subclinical complications was 15% for nephropathy, 31% for neuropathy and 39% for retinopathy. The minimum age at which incipient complications appear was 13 yr for one complication, 17 yr for the association of two complications, 23 yr for the association of three, after a diabetes duration of 3, 7, 15 yr, respectively.

CONCLUSIONS

In 30% of young diabetic patients without residual insulin secretion, it is possible to obtain mean annual HbA1c levels within the normal range. Increased frequency of HBGM and of clinic attendance help to reduce HbA1c levels. In contrast, multiple insulin injection therapy, allowing more freedom for diet, does not necessarily improve metabolic control and is associated with a higher incidence of severe hypoglycemic episodes. Incipient complications have to be looked for by sensitive methods from puberty.