Relationship between proliferative diabetic retinopathy and inflammatory markers in patients with type 1 diabetes in Brazil: a nested case control study.

Introduction This study examined the relationship between proliferative diabetic retinopathy (PDR) and serum levels of C-reactive protein, VEGF, TNF-⍺, and IL-6 inflammatory biomarkers, related to the pathophysiology of diabetic retinopathy. Methods This cross-sectional, case control study comprised 240 patients with type 1 diabetes (80 cases with PDR and 160 controls without diabetic retinopathy) who were matched for gender and duration of diabetes. Results C-reactive protein was the only inflammatory biomarker that was positively related to PDR (OR 1.96; 95% CI 1.01-3.78, p= 0.0045). We also noted an association between high glycated hemoglobin levels, the use of angiotensin-converting enzyme inhibitor, low glomerular filtration rate and PDR. Conclusion Patients with higher levels of C-reactive protein are more likely to present with PDR. We did not find a link between serum levels of VEGF, TNF-⍺ or IL-6 and PDR. The function of inflammatory biomarkers in PDR must be addressed in further studies.