LOW BLOOD-PRESSURE LEVELS IN LONG-TERM RETINOPATHY-FREE TYPE-I DIABETIC-PATIENTS

Ophthalmoscopy and fluorescin angiography were performed in two groups of subjects with long term (>15 yr) Type I (insulin-dependent) diabetes mellitus with (n=19) or without (n=19) diabetic retinopathy. The two groups were matched for diabetes duration (non-retinopathic (NR): 18.9+/-4.4 vs retinopathic (R): 20.6+/-6.0 yrs), metabolic control (HbA1c NR 7.5+/-1.4 vs R 8.3+/-1.4%) and BMI (NR 23.0+/-2.5 vs R 24.7+/-9.8). NR patients had significantly (p<0.001) lower systolic (NR 111.2+/-12.0 vs R 130.2+/-13.9 mmHg) and mean blood pressure levels (NR 82.8+/-7.7 vs R 92.2+/-9.0 mmHg). The group of retinopathic patients showed significantly (p<0.001) higher AER values (51.8+/-42 vs 7.9+/-4.5 mug/min). The prevalence rate of microalbuminuria (>20 mug/min) was 58% (11/19) in the R patients group whereas only one subject (the oldest patient - aged 55 yr - with the longest duration of diabetes - 30 yr) in the group of NR diabetic patients had a mean value of 20.2+/-3 mug/min. No significant difference was found in blood pressure values between retinopathic patients with microalbuminuria (128/76+/-14.2/11.1 mmHg) (AER: 77.8+/-33.8 mug/min) and those without microalbuminuria (130/75+/-16.0/12.7 mmHg) (AER: 9.38+/-4.81 mug/min). When only patients without microalbuminuria were considered, blood pressure values were still significantly higher (p<0.01) in R (n=8) (130/75+/-16.0/12.7) than in NR (n=18) (110/75+/-11.8/9.0) patients. Significantly higher systolic blood pressure values were found in the R patients (n=9) who received laser photocoagulation treatment than in R patients (n=10) who did not (136+/-16.2 vs 124+/-8.2 mmHg; p<0.05). The laser treated subgroup included 5/9 patients who had systolic blood pressure >140 mmHg vs 0/9 in the non-laser treated subjects. Positive family history for arterial hypertension was found in 10/19 retinopathic patients and 5/19 non-retinopathic patients (p<0.01). These data strongly suggest that blood pressure might influence the course of diabetic retinopathy in insulin-dependent subjects.