Associations of Diabetic Retinopathy Severity With High Ambulatory Blood Pressure and Suppressed Serum Renin Levels

The relationships between serum renin levels, severity of diabetic retinopathy (DR), and 24-hour blood pressure (BP) have not been previously reported.

To explore causes for DR and the relationships of 24-hour ambulatory BP, and hormone levels with the severity of DR.

The diabetic patients were classified as having no DR, simple DR, or severe DR (preproliferative DR plus proliferative DR) based on funduscopic examination, and we measured 24-hour BP, serum active renin (ARC), aldosterone (SAC), adrenocorticotropic hormone, and cortisol levels in each group.

Compared to those with no DR or simple DR, patients with severe DR showed significantly higher 24-hour BPs, including daytime and nighttime systolic and diastolic BP levels, independent of diabetic duration and HbA1c levels. The variability of nighttime systolic BP was greater in patients with severe DR than in those with nonsevere DR, although nocturnal BP reduction was similar between the groups. The ambulatory BPs were significantly inversely associated with ARC. The ARC was significantly lower in severe DR patients than in those with no DR or simple DR (3.2 [1.5-13.6] vs 9.8 [4.6-18.0] pg/mL, P < .05), but there were no differences in SAC in patients taking calcium channel blockers and/or α-blockers. No associations were found between DR severity and other hormone levels.

Severe DR was associated with higher 24-hour BPs and suppressed ARC. These findings suggest that mineralocorticoid receptor overactivation may play a role in higher BP levels and severe DR in diabetic patients.