[BP.09.05] SYSTOLIC BLOOD PRESSURE IS A RISK FACTOR FOR DEVELOPMENT AND PROGRESSION OF RETINOPATHY IN PATIENTS WITH TYPE 1 DIABETES AND NORMAL RENAL FUNCTION

Objective: It is well established that diabetic retinopathy is one of the leading causes of visual impairment and blindness in patients with type 1 diabetes (T1DM). It is assumed that retinopathy and nephropathy occurs at the same time and that the severity of retinopathy parallels the presence and severity on nephropathy in diabetes mellitus. The aim of this study was to evaluate the associations between systolic (SBP) and diastolic blood pressure (DPB) and risk for development or progression of nonproliferative retinopathy (NPR) in T1DM with normal renal function. Design and method: A total of 223 normoalbuminuric T1DM with normal or mildly decreased (estimated GFR > 60 mlmin-11.73m2) renal function were included in this study and followed for 48 months (age 42 ± 7 years, 120 M/113F, BMI 25 ± 4 kg/m2, HbA1c 7.0 ± 1.4%, duration of diabetes 17 ± 9 years, serum creatinine 70 ± 12 umol/L, estimated GFR 106 ± 15 mlmin-11.73 m2, urinary albumin excretion rate (UAE) 9.8 (1.3–29.0 mg/24 h). Estimated GFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. Microalbumin was measured spectrophotometrically by turbidimetric immuno-inhibition. Diagnosis of retinopathy was made by fundoscopy after pupillary dilatation. Blood pressure was measured twice in the sitting position with a mercury sphygmomanometer. The effects of SBP and DBP for development or progression of NPR were examined in backward stepwise Cox's multiple regression analysis. Results: The majority of patients (70%) had no retinopathy while 67 (30%) had NPR. Patients with NPR compared to patients without retinopathy were older (49 ± 8 vs 39 ± 6 years, p < 0.001), had longer duration of diabetes (24 ± 9 vs 14 ± 8 years, p < 0.001), higher BMI (25 ± 4 vs 24 ± 5 kg/m2, p = 0.004), higher systolic blood pressure (130 (95–160) vs 120 (80–180) mmHg, p = 0.03), higher UAE (10.3 (1.3–29) vs 7.8 (2.3–25.5) mg/24 h, p = 0.006) and lower estimated GFR (101 ± 17 vs 108 ± 13 ml min−1 1.73 m−2, p = 0.001). In backward stepwise Cox's multiple regression analysis systolic blood pressure was significantly associated with development or progression of NPR (relative risk 1.03 (CI 1.01–1.05), p = 0.02). Conclusions: Our results suggest that SBP is a risk factor for development and progression of NPR in T1DM even when coexisting renal disease is excluded.