[Prehypertension in type 1 diabetic children and adolescents].

Background: The elevated blood pressure is one of the most important risk factors of diabetic micro- and macroangiopathy.

Aim of the study: Evaluation of the prevalence of prehypertension and relationship between prehypertension, metabolic control and chronic complications in children and adolescents with type 1 diabetes mellitus.

Materials and methods: 83 patients aged 12.0-18.9 years, with a duration of diabetes 0.5-17.3 years, without evidence of arterial hypertension were recruited. In all patients 24-hour automatic blood pressure monitoring was performed with oscillometric device. The individuals with >40% of systolic and/or diastolic blood pressure >120/80 mmHg were defined as prehypertensive. HbA(1)c was measured by HPLC, plasma lipid levels--by an enzymatic method and urinary albumin excretion rate by chemiluminescent enzyme immunoassay method. Body mass index (BMI) and daily dose of insulin were calculated. Ophthalmoscopic examination and power spectral analysis of heart rate variation were performed.

Results: In 30 individuals (36.1%) prehypertension was diagnosed. The prehypertension group had older age (17.5+/-1.1 vs. 15.9+/-2.3 years; p<0.001) and longer duration of the disease (7.3+/-4.7 vs. 4.7+/-3.4 years; p=0.005) as compared with the group with normal blood pressure. There were no significant differences between groups in HbA1c, daily dose of insulin, BMI-SDS, lipids profile, prevalence of microalbuminuria and retinopathy. In the patients with prehypertension the a greater activity of sympathetic activation was observed (LF/HF: 1.00+/-0.06 vs. 0.78+/-0.04, p=0.018).

Conclusions: Prehypertension is frequently recognized in type 1 diabetic children and adolescents. The prevalence of prehypertension is associated with older age, longer duration of diabetes and the shift of the sympatho-vagal balance toward sympathetic activation. There is no relationship between prehypertension and metabolic control or the prevalence of microvascular complications.