Thirty-Year Trends in the Prevalence and Severity of Diabetic Retinopathy at the First Visit in Patients with Untreated Type 2 Diabetes Mellitus

Abstract

ABSTRACT Purpose Although the rate of diabetic retinopathy (DR)-related blindness has decreased in developed countries in recent years, the reasons for this decrease have remained unclear. The prevalence/severity trends of DR at the first visit in patients with untreated type 2 diabetes mellitus (T2DM) patients seen between the1986s and 2018s were assessed. Methods A total of 1979 Japanese T2DM patients diagnosed between 1986 and 2018 were divided into four groups by the decade of their first visit: the 1986 years (1986–1987), the 1996 years (1996–1997), the 2006 years (2006–2008), the 2016 years (2016–2018). The DR prevalence/severity trends were assessed. Results A significant decrease in the rate of prevalence of DR from the 1986s to 2016s was observed among previously untreated T2DM patients visiting our hospital for the first time (1986s: 25.5%; 1996s: 26.2%; 2006s: 22.2%; and 2016s: 15.6%). The prevalence was significantly higher in females (30.2%) than in males (21.3%). Although the severity trend of DR did not differ significantly among the four measurement years, the rate of simple DR was the highest in the 2016s. Conclusion We found, for the first time, a significant decrease in the rate of prevalence of DR from the 1986s to 2016s in patients with untreated T2DM visiting our hospital for the first time. A decrease in the rate of DR prevalence could explain, at least in part, the observed reduction in the rate of blindness in patients with T2DM.