[Significance of arterial blood pressure for the development of microalbuminuria and retinopathy in type I diabetes mellitus]

Abstract

The role of hypertension for the combined occurrence of incipient diabetic nephropathy and diabetic retinopathy (RP) was evaluated in 155 insulin-dependent diabetic patients (74 male/81 female); mean age 32.4 +/- 12.2 STD years; means diabetes duration 12.8 +/- 10 STD years). Albumin excretion rate (AER) was measured in 24 hours urine samples by RIA, retinal status was determined by both, fundoscopy and fluorescein angiography. Analysis of the data revealed a statistically significant correlation between the duration of disease and elevated AER (p less than 0.012), and the occurrence of retinopathy (p less than 0.0001). Although there was a close correlation between retinopathy and elevated AER (p less than 0.0001), it is remarkable that 31% of the patients with normal AER (less than 15 micrograms/min) showed signs of non proliferative RP. On the other hand 30% of patients without retinal changes showed an elevated AER (less than 15 micrograms/min). In the group of microalbuminuric patients (greater than 15 micrograms/min) systolic (p less than 0.004) and diastolic (p less than 0.04) blood pressures were significantly higher than in normoalbuminuric patients (less than 15 micrograms/min). Patients with proliferative retinopathy showed significantly higher systolic and diastolic (p less than 0.015) blood pressures compared to patients without retinal changes, though albumin excretion rates were not different in both groups of patients. In conclusion, our results show that diabetic nephropathy and diabetic retinopathy do not develop simultaneously in a representative number of insulin-dependent diabetic patients, but hypertension may be a major risk factor for the development of both microangiopathic complications.