This study included adult patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) who had undergone renal biopsy. Patients were classified based on pathological diagnosis, univariate and multivariable regression analyses were performed to evaluate associations between macular thickness and pathologically diagnosed DN.

A total of 206 patients meeting the inclusion and exclusion criteria were finally included in the study. We classified the patients into three categories: Isolated DN (n = 55), Isolated non-diabetic renal disease (NDRD) (n = 94), and DN combined with NDRD (n = 57). The results indicated that patients with DN had significantly increased retinal thickness. Multivariate binary logistic regression showed that diabetes duration, smoking, diabetic retinopathy (DR), fibrinogen, low-density lipoprotein cholesterol (LDL-C), outer temporal macular thickness were independently associated with DN (P < 0.05). The relationship between outer temporal macular thickness and DN was significant regardless of whether the combined group was included in DN or NDRD, and the diagnostic efficiency of the model was improved when the combined group was excluded.