Diabetes Distilled: Retinopathy differentiates nephropathy type but not severity in diabetes

By Colin Kenny, Editor – Diabetes Distilled
 
Diabetic retinopathy (DR) is the most common microvascular complication of diabetes. Researchers wanted to discover whether DR had utility in distinguishing another microvascular complication, diabetic nephropathy (DN), from non-diabetic nephropathy disease (NDRD). Investigators analysed 45 studies that evaluated DR for the diagnosis of DN in patients with type 2 diabetes and kidney disease. They found that DR helped differentiate DN from NDRD but the diagnostic accuracy of the test was not as high as expected. Researchers also found that the severity of DR might not parallel the presence of DN.
 
Investigators performed a comprehensive meta-analysis of all published studies comparing DR that used histopathological examination in the diagnosis of DN. They searched all relevant databases. Their analysis included patients with type 2 diabetes; they assessed the accuracy of DR for differentiation between patients with DN and those with NDRD; and they also analysed pathological evaluations of renal biopsy specimens.
 
The investigators identified 45 relevant studies that included a total of 4561 patients with type 2 diabetes and kidney disease in which biopsy specimens were also routinely processed. They found DR helped differentiate DN from NDRD, although the test had a sensitivity of 0.67 and specificity of 0.78, which was lower than may have been expected. When compared to DR, proliferative DR – which is the most severe form of the condition – was found to be a poor measure of diagnostic performance despite having a very high specificity for the diagnosis of DN (0.99). This finding suggests that, in patients with type 2 diabetes, there may be no equivalent relationship between DR severity and the presence of DN.
 
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