Objectives To explore the relationship between diabetic macular edema (DME) classified by different optical coherence tomography (OCT) types and the risk of diabetic nephropathy (DN). MethodsA retrospective clinical study. A total of 304 patients with DME, involving 421 eyes, diagnosed through ophthalmic examinations at Xi'an Third Hospital between August 2019 and December 2024 were included in the study. All affected eyes underwent OCT examination along with laboratory tests including glycated hemoglobin, serum albumin, serum creatinine, glomerular filtration rate, urine albumin-to-creatinine ratio, serum β2-microglobulin, and 24-hour urine protein quantification. Based on OCT imaging characteristics, DME was classified into diffuse retinal thickening (DRT) type, cystoid macular edema (CME) type, and serous retinal detachment (SRD) type, with corresponding group sizes of 96 patients (138 eyes), 102 patients (132 eyes), and 106 patients (151 eyes), respectively. The risk of DN development was categorized as low, moderate, high, or very high risk according to KDIGO guidelines. Intergroup comparisons of renal function-related indicators were performed using nonparametric tests. ResultsThe number of affected eyes classified as low risk for DN in the DRT, CME, and SRD groups were 87, 72, and 63, respectively. The number classified as moderate risk were 23, 23, and 28, respectively. The number classified as high risk were 22, 27, and 35, respectively. The number classified as extremely high risk were 6, 10, and 25, respectively. These differences were statistically significant (χ2=20.359, P=0.002). Serum albumin levels were (44.66±4.89), (43.59±6.41), and (41.31±7.53) g/L, respectively. Serum β2-microglobulin levels were (2.15±1.55), (2.52±2.34), and (4.09±5.57) mg/L, respectively. The 24-hour urine protein quantification was (94.88±64.58), (106.20±75.49), and (151.38±121.88) mg/24 h, respectively. Low serum albumin levels were (32.58±1.84), (31.58±2.13), and (30.15±1.63) g/L, respectively. 24-hour high urine protein levels were (225.15±59.78), (246.96±67.38), and (317.71±96.52) mg/24 h, respectively. High serum β2-microglobulin levels were (5.51±3.03), (7.80±3.63), and (14.60±6.81) mg/L, respectively. The comparison of indicators related to renal function showed that there were statistically significant overall differences among the three groups in serum albumin, serum β2-microglobulin and 24-hour urine protein quantification (χ2=18.367, 18.674, 14.612; P＜0.001). The SRD group presented more significant characteristics of renal function impairment. Its low serum albumin level was lower than that of the DRT and CME groups, while the 24-hour high urine protein quantification and high serum β2-microglobulin level were significantly higher than those of the other two groups, and the differences were statistically significant (χ2=21.587, 21.344, 21.587; P＜0.001). ConclusionDN is an important risk factor for SRD-type DME, and patients with this type often have more severe abnormal markers of renal function impairment.
