The effect of insulin pump therapy in retinal vasculature in type 1 diabetic patients

Continuous subcutaneous insulin infusion (CSII) is a treatment for type 1 diabetes that improves metabolic control and reduces micro and macrovascular complications. The aim of this study was to compare the effect of CSII versus traditional multiple daily injections (MDI) therapy on retinal vasculature.

We performed a prospective study with type 1 diabetic patients with no prior history of ocular pathology other than mild diabetic retinopathy. The patients were divided into two groups according to their therapeutic modality (CSII vs MDI). The retinal nerve fiber layers thickness and vascular densities were compared between groups in both macula and optic disc. The correlations between vascular density and clinical features were also determined. Statistical significance was defined as p < 0.05.

The study included 52 eyes, 28 in the insulin CSII group. The mean age was 36.66 ± 12.97 years, with no difference between groups (p = 0.49). The mean glycated hemoglobin (HbA1c) was found to be lower in the CSII group (7.1% ± 0.7 vs 7.5% ± 0.7 p < 0.01). The parafoveal vascular density was found to be higher in the CSII group (42.5% ± 0.4 vs 37.7% ± 0.6, p < 0.01). We found an inverse correlation between HbA1c value and parafoveal vascular densities (p < 0.01, r = -0.50).

We found that CSII provided better metabolic control than MDI and this seemed to result in higher parafoveal vascular density. As lower vascular density is associated with an increased risk of diabetic retinopathy, these results suggest that CSII could be the safest therapeutic option to prevent retinopathy.