Diabetic retinopathy Is associated with histologic severity of diabetic kidney disease and systemic inflammation

This study investigated the association between diabetic retinopathy (DR) and histologic features in patients with histologically confirmed diabetic kidney disease (DKD).

Of 250 patients who underwent kidney biopsy, 108 patients with biopsy-confirmed DKD were included (DKD with DR, n = 71; DKD without DR, n = 37). DKD was classified into classes I-IV using the Renal Pathology Society Classification. Systemic inflammation was assessed using the red blood cell distribution width/albumin ratio (RAR) and C-reactive protein (CRP) levels.

Patients in the DR (+) group were younger and had higher systolic blood pressure. They exhibited significantly lower estimated glomerular filtration rate (36.7 vs. 59.9 mL/min/1.73 m², p = 0.001) and serum albumin (3.4 vs. 3.9 g/dL, p = 0.001). While CRP levels did not differ between groups, RAR was significantly higher in the DR (+) group (3.935 vs. 3.407, p = 0.003). Histologically, kidney injury was more severe in the DR (+) group, with higher frequencies of class III (54.9% vs. 37.8%) and class IV (35.2% vs. 18.9%) disease. Linear deposition of immunoglobulin (Ig) G and light-chain positivity on immunofluorescence staining were also more common in the DR (+) group (IgG: 66.2% vs. 43.2%; light-chain : 53.5% vs. 29.7%).

In biopsy-confirmed DKD, the presence of DR is associated with more severe renal pathology and increased systemic inflammation. These findings support the clinical relevance of DR screening in patients with DKD and highlight the need for prospective validation.