Improving visual prognosis of the diabetic patients during the past 30 years based on the data of the Finnish Register of Visual Impairment

Purpose To evaluate changes in visual impairment (VI) due to diabetic retinopathy (DR) recorded in the Finnish Register of Visual Impairment (RVI) during the past 30 years. Methods Data from the visually impaired diabetic persons included in the RVI were analysed using three 10‐year cohorts (1982–90, 1991–2000, 2001–10). Information on the age at the time of the first VI registration, severity of VI determined according to the World Health Organisation (WHO) definition, and the age at death was collected. VI due to proliferative (PDR) and non‐proliferative (NPDR) DR were analysed separately. Results Data of 4080 patients whose primary cause for VI was DR were analysed. The median age at the time of notification of VI for the three cohorts was 39, 62 and 59 years in the PDR group and 71, 73 and 73 in the NPDR group, respectively. The proportion of blind persons was 42%, 22% and 15% in the PDR group and 10%, 9% and 4% in the NPDR group, respectively. The median age at death in the three cohorts was 54, 73 and 72 years in PDR group and 76, 79 and 80 years in the NPDR group, respectively. The standardized mortality ratio (SMR) compared with the general population was 8.3, 2.9 and 1.4 in persons with PDR and 3.4, 2.0 and 1.2 in those with NPDR, respectively. Conclusions A significant change in the profile of the VI in the PDR group has taken place in Finland. It was characterized by increased age at the time of VI notification, decreased severity of VI and higher age at death. Most evidently these improvements took place in the 1990s. The profile of VI in the NPDR group has changed only modestly. Compared with the general population, SMRs improved both in NPDR and PDR groups continuously.