Ambulatory Blood Pressure and Heart Rate in Adolescents with Insulin-dependent Diabetes Mellitus

Abstract

Background The aim of the study was to analyse the effect of insulin-dependent diabetes mellitus (IDDM) on blood pressure (BP), circadian BP profile, BP variability and heart rate (HR) in adolescents.
Methods The study population consisted of 50 adolescents (mean age = 17.0 ± 2.5 years) with a mean duration of IDDM 8.4 t 3.7 years without clinical symptoms of neuropathy All patients were given human insulin in a mean daily dose 0.93 ± 0.23 µ/kg. Mean HbA1c was 8.9% ± 1.8%; nocturnal albuminuria remained within the limits of normal. A group of 50 subjects with normal carbohydrate metabolism matched for gender and age served as controls. 24hr ambulatory blood pressure and heart rate recordings (SpaceLabs 90207) were taken every 30 min. BP and HR variability was assessed as standard deviations of all measurements. One-way analysis of variance was performed to compare the results.
Results Adolescents with IDDM compared with healthy controls had significantly higher nocturnal: systolic BP ( 108.1 ± 8.3 vs 104,7 ± 7,3 mm Hg, p < 0.05), diastolic BP (61.1 ± 6.2 vs 57.0 ± 4.2 mm Hg, p < 0.001 ) and heart rate (69.7 ± 10,5 vs 65,5 ± 10,03/min, p < 0.05). IDDM patients showed also decreased diurnal-nocturnal differences for: systolic BP (10.2% ± 3.8% vs 12,2% ± 4.5%, p < 0.05), diastolic BP (16.9% ± 7.8% vs 20.9% ± 6.3%, p < 0.01) and heart rate (18.8% ± 9.2% vs 22.9% ± 8.2%, p < 0.05). BP and HR variability did not differ significantly between the groups.
Conclusions Higher BP and HR at night and reduced diurnal-nocturnal BP and HR difference seem to be an early sign of sympatho-vagal imbalance among adolescents with IDDM.