Ambulatory Blood Pressure in the Transition from Normo- to Microalbuminuria: A Longitudinal Study in IDDM Patients

To describe the development in blood pressure (BP) in relation to urinary albumin excretion (UAE) more exactly, 44 initially normoalbuminuric type I diabetic patients and 21 healthy individuals were included in a 3.1-year follow-up study by using ambulatory BP (AMBP) monitoring. Six patients developed microalbuminuria according to accepted criteria (progressors; UAE at follow-up was > 20 micrograms/min). Initial UAE was higher in this group (9.0 x/divided by 1.4 micrograms/min) compared with both the nonprogressors (5.2 x/divided by 1.6 micrograms/min) and the control subjects (3.9 x/divided by 1.6 micrograms/min), P < 0.01. The values were almost identical for initial 24-h AMBP between the progressors and the two other groups. The transition to microalbuminuria (31.7 x/divided by 1.8 micrograms/min) was associated with an increase in 24-h systolic AMBP of 11.5 +/- 8.3 mmHg, which was significantly higher than the increase in the nonprogressors (3.1 +/- 7.7 mmHg) and the control subjects (2.2 +/- 6.1 mmHg, P = 0.02). Significant correlations were detected between development in UAE and development in systolic and diastolic 24-h AMBP (r = 0.39, r = 0.41, P < 0.01). In addition, an increase in UAE, even including increases within the normoalbuminuric range, was always associated with an increase in 24-h AMBP (P < 0.01). Ordinary clinical measurements did not reveal any of these differences or correlations. In conclusion, a close association between increases in UAE and 24-h AMBP emerges in this study. Initial BP was not increased in the progressors.(ABSTRACT TRUNCATED AT 250 WORDS)