Variations of ambulatory blood pressure with position in patients with type 1 diabetes: influence of disease duration and microangiopathy in a pilot study

Abstract

Objective: To study the influence of position changes on 24-h ambulatory blood pressure (ABP) in normotensive or mildly hypertensive normoalbuminuric patients with type 1 diabetes.

Research design and methods: A cross-sectional evaluation of patients was staged according to the duration of diabetes (DD) and the presence of microangiopathy. We recruited 37 patients (30 men and 7 women), aged 38 +/- 12 years, who were normotensive or mildly hypertensive (diastolic blood pressure [DBP] <105 mmHg) and free of antihypertensive treatment and microalbuminuria. They were included according to DD (group 1, <5 years; group 2, > or =10 years). An additional group of seven diabetic patients with microalbuminuria and mild untreated hypertension was also investigated. We recorded 24-h ambulatory blood pressure every 15 min with a position sensor, which allowed for the discrimination between standing or supine/sitting position in the patient.

Results: Mean daytime (10:00 A.M. to 8:00 P.M.) ABP in supine/sitting position did not significantly differ between groups 1 and 2. However, standing ambulatory systolic blood pressure (ASBP) and ambulatory DBP (ADBP) were significantly higher than supine/sitting ASBP and ADBP in group 1 (DeltaSBP 4 +/- 5, DeltaDPB 4 +/- 6 mmHg, P < 0.01) but not in group 2 (DeltaSBP 2 +/- 8, DeltaDBP 2 +/- 4 mmHg, P = NS). Patients free of microangiopathy presented with significantly higher ABP in standing position than in sitting/lying position, whereas patients with retinopathy and/or nephropathy exhibited no significant increase of ABP during standing.

Conclusion: The monitoring of position during ambulatory measurement of blood pressure in type 1 diabetic patients shows different patterns in relation to disease duration and the presence of microangiopathy.