The relationship between the development and progression of microalbuminuria and arterial blood pressure in type 1 (insulin-dependent) diabetes mellitus.
OBJECTIVE
to investigate the association between urinary albumin excretion and arterial blood pressure in type 1 (insulin-dependent) diabetes.


METHODS
urinary albumin excretion and blood pressures were followed prospectively for a mean period of 26 months (range 18-29 months) in 46 young type 1 (insulin-dependent) diabetic subjects without overt nephropathy. Supine blood pressures (BP) were measured by a single observer using a random zero sphygmomanometer. Albumin excretion was assessed at baseline by a timed clinic excretion rate (AER; microalbuminuria = AER greater than 33 micrograms/min), and at follow-up in at least two urine specimens by the albumin/creatinine (A/Cr) ratio (micro-albuminuria = A/Cr greater than 3.7 mg/mmol).


RESULTS
39 subjects initially had normal AERs. Seven had developed microalbuminuria at follow-up: their mean BP rose from 114 +/- 13/62 +/- 13 to 119 +/- 7/77 +/- 5 mmHg (for diastolic BP, P less than 0.05), while there was no change in the mean BP in the remaining 32 patients. A rise in diastolic BP of greater than 10 mmHg occurred in five of the seven subjects who developed microalbuminuria, and in only seven of 32 who did not (P = 0.02). In the seven patients in whom microalbuminuria persisted (n = 3) or progressed to overt proteinuria (n = 4), BP increased from 123 +/- 12/70 +/- 14 to 139 +/- 12/88 +/- 10 mmHg (P less than 0.02 for both).


CONCLUSIONS
this study has shown that BP is normal before the onset of microalbuminuria, and that a rise in diastolic BP accompanies the development or progression of microalbuminuria. The rate of rise in BP may be more important than the absolute level in defining 'hypertension' in young diabetic patients with microalbuminuria.
Raal
F J
FJ
Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa.
Kalk
W J
WJ
Taylor
D R
DR
Osler
C E
CE
Panz
V R
VR
D000328:Adult; D000419:Albuminuria; D001794:Blood Pressure; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology* / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D011446:Prospective Studies; D016683:Supine Position
D006442:Glycated Hemoglobin