We thank Dr. Azar and colleagues for their interest in our article (1) on the low prevalence of cardiovascular disease (CVD) in patients with long duration of type 1 diabetes without proliferative diabetic retinopathy (PDR) but with diabetic kidney disease. Their results, presented in the accompanying letter (2), showed an association of the severity of diabetic retinopathy (DR) with future CVD events and are important and consistent with our findings. The shorter duration of diabetes in the French cohort compared with the 50-Year Medalist Study cohort suggests that the risk factors for CVD are related to the severity of PDR. The duration in the cohort studied by Azar et al. was 22 years, a time period when DR is still progressing, whereas this is unlikely in the Medalists and in the Finnish Diabetic Nephropathy Study (FinnDiane) patients with longer duration of diabetes at the time of the study (53 years and 33 years, respectively), as shown in our subsequent study (3). Thus, our cohorts indicate that there could be common protective factors for CVD and PDR. However, the additional data from Azar et al. (2), with shorter diabetes duration, further strengthen the hypothesis on a link between PDR and CVD. Additional studies, both longitudinal and mechanistic, are warranted to identify common risk and protective factors leading to the development of DR and CVD.
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Duality of Interest. No potential conflicts of interest relevant to this article were reported.
