High-normal blood pressure and early diabetic nephropathy.

The relationship between high-normal blood pressure (BP) levels and early diabetic nephropathy is currently unknown. Blood pressure levels were checked longitudinally for a mean of 6.6 years in 230 subjects to determine their relationship to early diabetic nephropathy as monitored by microalbuminuria. High-normal BP level correlated with the presence of microalbuminuria. Microalbuminuria was 2.8 times as common in subjects with high-normal BP levels compared with those subjects with BP levels below the 90th percentile for their age. The elevated microalbumin excretion was primarily associated with high-normal diastolic BP levels. Our data suggest that either microalbuminuria or high-normal BP levels can precede the other. In a logistics model, diastolic BP and mean HbA1 (over 6.6 years) entered the model at similar levels, followed by duration of diabetes. When the influence of mean HbA1 was removed using logistic regression, the diastolic BP level remained a significant associated factor for the presence of microalbuminuria.