Purpose: In this study, we examine the association of blood pressure (BP), retinal thickness (RT), and vessel caliber in patients with type 2 diabetes and high HbA1c (elevated long-term blood glucose) with or without mild or moderate nonproliferative diabetic retinopathy (NPDR).
Methods: Forty-three patients with type 2 diabetes and high HbA1c measures (23 without NPDR and 20 with mild to moderate NPDR) and 22 age-matched nondiabetic controls participated. The BP, RT (Stratus OCT3), fundus photography, and HbA1c were measured. Correlations between BP, HbA1c, vessel caliber, and RT were evaluated.
Results: Diastolic BP (DBP) is positively and significantly associated with RT in patients with NPDR (p < 0.02). Blood pressure was not associated with RT in patients without NPDR (p = 0.83). There is an association between higher HbA1c and higher DBP within the NPDR group (p < 0.02). Furthermore, HbA1c modifies the slope of the relationship between DBP and RT in NPDR patients. Greater venule diameters and loss of the correlation between decreased arteriole size and increased systolic blood pressure, seen in controls, were observed in patients with and without NPDR.
Conclusions: The results of this study show that HbA1c and BP together have an impact on RT measures of patients with DR. These measures should be considered when evaluating RT in patients with DR both clinically and in future optical coherence tomography studies on this population.