Effect of microalbuminuria on macular thickness in patients with type-2 diabetes mellitus

To investigate the effect of microalbuminuria on macular thickness in patients with type-2 diabetes mellitus with no or mild diabetic retinopathy and to investigate the relationship between macular thickness and metabolic parameters.

Fifty eight eyes of 58 patients without diabetic retinopathy (group 1) in microalbuminuria stage, 42 eyes of 42 patients with mild diabetic retinopathy (group 2) in microalbuminuria stage, and 50 eyes of 50 patients without diabetic retinopathy and microalbuminuria (group 3) were included in this study. After detailed ophthalmologic examination, all patients underwent spectral domain-optical coherence tomography measurements. Macular thickness was noted from nine different areas (fovea, four parafoveal, and four perifoveal areas) and compared between groups. The correlations between macular thickness and age, duration of diabetes mellitus, microalbuminuria, serum urea, creatinine, glycosylated hemoglobin (HbAIc), albumin, sodium (Na), and urinary Na were evaluated.

The mean age was 53.29 ± 6.49 in group 1, 55.86 ± 6.97 in group 2, and 52.98 ± 5.66 years in group 3 (p = 0.06). The macular thickness values of superior, inferior, and nasal parafoveal areas were significantly different between groups (p = 0.001, p = 0.006, and p = 0.03, respectively). Bonferroni post test revealed that this difference originated from the difference between group 2 and 3 (p < 0.05 for all values). There were significant negative correlations between the macular thickness values of parafoveal areas and serum urea, HbA1c, albumin, microalbuminuria levels (p < 0.05 for all values).

In this study, a significantly decreased parafoveal macular thickness was measured in patients with mild diabetic retinopathy and microalbuminuria compared to patients without diabetic retinopathy and microalbuminuria.