Recently, we reported that total bilirubin concentration (TBC) is an important risk factor for diabetic retinopathy. On the other hand, hypertension is reported to be a risk factor for diabetic retinopathy. Therefore, we compared systolic blood pressure (SBP) and TBC in terms of risk factor for retinopathy.Design and Method:
Six hundred and sixty six patients (440 men) with type 2 diabetes mellitus were investigated in this cross-sectional study. SBP and TBC were compared between the patients with and without retinopathy by unpaired t-test. Correlation between SBP and TBC was tested using Pearson's correlation coefficients. Logistic regression analysis was performed to examine the effects of various factors on retinopathy, and the following factors were considered as independent variables: SBP, TBC, gender, age, diabetes duration, BMI, HbA1c, eGFR, LDL-cholesterol, and triglyceride.Results:
The age, diabetes duration, HbA1c, SBP, and TBC of 666 patients were 64.7 ± 13.9 years, 13.9 + 10.9 years, 9.1 + 2.1 %, 133.7 + 22.4 mmHg, and 0.74 + 0.36 mg/dl. Two hundred and seventy five (41%) patients had retinopathy. SBP was higher in patients with retinopathy (137.8 + 24.5 vs. 130.8 + 24.5 mmHg, p < 0.01) than in those without retinopathy. TBC was significantly lower in patients with retinopathy (0.65 + 0.30 vs. 0.80 + 0.39 mg/dl, p < 0.01) than in those without retinopathy. SBP and TBC did not correlate (r = -0.046, p = 0.23). The results of logistic regression analysis showed that SBP (p < 0.01), TBC (p < 0.05), age (p < 0.05), diabetes duration (p < 0.01), HbA1c (p < 0.05), and eGFR (p < 0.01) were independent explanatory factors for retinopathy.Conclusions:
In diabetic patients, SBP was higher and TBC was lower in those with retinopathy. High SBP and low TBC in diabetic patients might have pathophysiological significance in the onset of retinopathy.