Within-Visit Systolic Blood Pressure Variability: An Indicator of Diabetic Retinopathy

Objective: To discuss whether within-visit blood pressure variability (BPV) increases the risk of diabetic retinopathy (DR) after adjusting for the conventional metabolic risk factors and to evaluate the independent impact of BPV to DR in diabetic patients. Methods: The study featured 625 patients with T2DM based on physical and biochemical tests. Among them, 66 patients had DR, and 66 HbA1c matched subjects without the condition (NDR group) were therefore handpicked from the remaining 559 participants in a ratio of 1:1. Three systolic BP (SBP) and diastolic BP (DBP) readings were recorded by physicians during a single medical assessment. Within-visit BPV for each subject was defined using the standard deviation of SBP (SBPSD) and DBP (DBPSD), coefficient of variation of SBP (SBPCV) and DBP (DBPCV). Results: No significant differences were found in laboratory testing parameters as well as general clinical data between the two groups (P＞0.05), but cases of DR had higher SBPSD (2.88±2.41 vs 3.76±2.63, P=0.046) and SBPCV (1.92±1.63% vs 2.29±1.56%, P=0.036) than NDR subjects. SBPSD and SBPCV were both independent statistical indicators of DR after adjusting for age, gender, smoking history, alcohol consumption, obesity, history of hypertension, SBPM, DBPM, HbA1c and TC [OR: 1.188, 95%CI: 1.030-1.370, P=0.018 and OR: 1.271, 95%CI: 1.031-1.566, P=0.025, respectively]. Conclusion: In T2DM patients, elevated within-visit SBPV associates strongly with DR in spite of no statistical difference in metabolic indicators. Even to the same degree of blood glucose control, within-visit SBPV is an independent indicator of DR.