Retinopathy Severity Linked to Nerve and Kidney Damage in Type 2 Diabetes: Study
Researchers have found that the severity of diabetic retinopathy (DR) and the presence of diabetic macular edema (DME) are closely linked to both peripheral neuropathy and early kidney damage in patients with type 2 diabetes mellitus (T2DM). The study was published in the journal BMC Ophthalmology by Sara R. and colleagues. Neuropathy, retinopathy, and nephropathy are the three diabetic microvascular complications that are major causes of morbidity in T2DM.
This cross-sectional study consisted of adult participants diagnosed with T2DM with a minimum duration of five years, having preserved renal function defined as an estimated glomerular filtration rate of eGFR ≥ 60 mL/min/1.73 m². The grading of diabetic retinopathy was based on the International Clinical Diabetic Retinopathy Severity Scale, while DME was assessed by spectral-domain OCT. Peripheral neuropathy was quantified using NCS, with a primary focus on sural sensory SNAP amplitude. Nephropathy was assessed by both UACR and eGFR measurements. Accordingly, neuropathy, retinopathy, and nephropathy were assessed in 155, 138, and 94 patients, respectively. These comprehensive evaluations allowed for an integrated analysis of how retinal disease correlates with nerve and kidney health in the same population.
Results
Among the 138 participants who underwent fundus examinations, 60% had PDR, while 32% showed DME.
Statistical analysis showed that SNAP amplitude was inversely correlated with the severity of DR (p = 0.001) and the presence of DME (p = 0.001), indicating that with the increase in the severity of the retinal disease, there was deterioration of nerve conduction, a true hallmark of shared microvascular damage.
DME patients had a fourfold greater risk of impaired SNAP values compared to those without DME (OR = 4.0; 95% CI: 1.849–8.653), reflecting the strong association between macular pathology and peripheral nerve dysfunction.
Moreover, UACR levels were higher in patients with DME (p = 0.011), a marker of kidney injury.
The severity of nephropathy showed a mild but significant correlation with DR stage (p = 0.047), strengthening the association between changes in the retinal and renal microvasculature.
These results together suggest that the severity of DME and DR might serve as a visible, quantifiable marker for the progression of systemic microvascular disease in T2DM.
This study showed that the severity of diabetic retinopathy and the presence of DME are strongly related to peripheral neuropathy and increased albuminuria in patients with T2DM, supporting the concept of shared microvascular pathology across the eye, nerves, and kidneys.
Reference:
Roostaei, S., Ashraf, A., Fard, M.V. et al. Interrelationship of diabetic neuropathy, retinopathy and nephropathy in type 2 diabetes mellitus: a cross-sectional analysis. BMC Ophthalmol 25, 604 (2025). https://doi.org/10.1186/s12886-025-04470-5
