Rapid reduction of HbA1c and early worsening of diabetic retinopathy: A real-world population-based study in subjects with type 2 diabetes
Objective: Early worsening of diabetic retinopathy (EWDR) due to the rapid decrease of blood glucose levels is a concern in diabetes treatment. The aim of the present study was to evaluate whether this is an important issue in subjects with type 2 diabetes with mild or moderate non-proliferative DR (NPDR), which represent the vast majority of subjects with DR attended in the Primary Care.
Research Design and Methods: retrospective nested case-control study of subjects with type 2 diabetes and previous mild or moderate NPDR. Using SIDIAP (“Sistema d'informació pel Desenvolupament de la Recerca a Atenció Primària”) database, we selected 1,150 individuals with EWDR and 1,150 matched controls (DR without EWDR). The main variable analyzed was the magnitude of the reduction of HbA1c in previous 12 months. The reduction of HbA1c was categorized in rapid (>1.5% reduction in < 12 months) and very rapid (>2% in <6 months).
Results: We did not find any significant difference in HbA1c reduction between cases and controls (0.13±1.21 vs. 0.21±1.18; p=0.12). HbA1c reduction did not show significant association with worsening of DR, neither in the unadjusted analyses nor in adjusted statistical models that included the main confounding variables: duration of diabetes, baseline HbA1c, presence of hypertension and antidiabetic drugs. In addition, when stratification by baseline HbA1c was performed we did not find that those patients with higher levels of HbA1c presented higher risk to EWDR.
Conclusion: Our results suggest that the rapid reduction of HbA1c is not associated with progression of mild or moderate NPDR.