The impact of blood pressure measurement methods on the assessment of differences in blood pressure levels between patients with normoalbuminuric type 1 diabetes and healthy controls

The aim of the study was to investigate the impact of various blood pressure (BP) measurement methods on the assessment of differences in BP levels between patients with normoalbuminuric type 1 diabetes and healthy controls. We measured intra-arterial BP (i.a.), sphygmomanometric BP (sphygmo), 24-h ambulatory blood pressure (ABPM, auscultatory, Profilomat(R)) and oscillometric BP (Dinamap(R)) in 51 patients with normoalbuminuric type 1 diabetes (DP) with a mean diabetes duration of 8.4 years and 42 healthy controls (C). Results are expressed as mean rt SE. There was no significant difference in i.a. BP between DP and C (systolic/diastolic BP and mean arterial pressure (MAP) 116.2 +/- 1.2/61.7 +/- 0.8 (82.8 +/- 0.9) mm Hg in DP vs 115.6 +/- 1.2/63.2 +/- 0.9 (83.4 +/- 1.1) in C). Sphygmo BP was 117.7 +/- 1.3/69.8 +/- 1.0 mm Hg in DP vs 116.5 +/- 1.5/67.8 +/- 1.3 in C (NS). Also, ABPM was not significantly different between both groups. Daytime BP between 10.00-23.00 h was 120.9 +/- 1.2/84.4 +/- 0.9 mm Hg in DP vs 120.4 +/- 1.5/83.7 +/- 1.0 in C (NS). Night-time BP between 01.00-07.00 h was 102.4 +/- 1.2/69.3 +/- 0.9 mm Hg in DP vs 103.4 +/- 1.5/69.1 +/- 1.3 in C (NS). In contrast, systolic Dinamap(R) BP was higher in DP (118.6 +/- 1.3 in DP vs 113.4 +/- 1.4 mm Hg in C, P = 0.01) as was MAP (85.6 +/- 0.7 in DP vs 83.3 +/- 1.0 mm Hg in C, P = 0.05). Diastolic Dinamap(R) BP was not significantly different (66.6 +/- 0.7 in DP vs 65.0 +/- 1.0 mm Hg in C). We conclude that intra-arterial BP was similar in patients with normoalbuminuric type 1 diabetes and healthy controls. Also, when using auscultatory BP devices there were no apparent differences in blood pressure. In contrast, using the oscillometric method (Dinamap(R)), BP especially systolic, was higher in diabetic patients. Measurements with an oscillometric device (Dinamap(R)) might therefore overestimate BP in patients with normoalbuminuric type 1 diabetes, thus confusing conclusions on the relationship between development of hypertension and microalbuminuria in the early phase of diabetes.