OBJECTIVES: Proliferative diabetic retinopathy (PDR) is the most advanced stage of diabetic retinopathy (DR) which is characterised by presence of neovascularization. PDR is the leading cause of blindness among working-age individuals in developed nations with a greater vision-related functional burden. This study aims to gather evidence related to the epidemiology of PDR among diabetics.

METHODS: A targeted literature search was performed for studies published in English from database inception to January 2019 in Embase, MEDLINE, MEDLINE-In Process, and Cochrane library. Studies reporting data on the incidence or prevalence of PDR among diabetic patients were included.

RESULTS: Literature findings suggest an age-standardised prevalence rate of 7.24% (95% CI: 7.15 to 7.33) for PDR (world diabetes population in 2010) leading to estimated 17.2 million patients worldwide. Identified studies showed varied prevalence rates [UK (0.5% to 6.4%), Australia (4.3%), China (3.9%), Spain (2.1%), Germany (2.0%), Rural-China (0.42%)] and cumulative incidence rates [Sweden, 10-year (1.8%), Mauritius, 6-year (0.4%)]. Specifically, among type 2 diabetes mellitus (T2DM) patients, cumulative incidence rates ranged from 0.5% (Hong Kong, 4-year) to 15.4% (US Indians, 14-year). Reported data also suggests that the prevalence rate among T2DM patients was lowest for Whites (0.9% to 2.6%) followed by Blacks (1.8% to 4.2%) and then Hispanics (3.8% to 6.3%). Moreover, the likelihood of getting PDR rises exponentially with increase in diabetes duration up to ≥20 years compared to T2DM patients with <10 years [T1DM, RR = 15.33 (95% CI: 11.29 to 20.8); T2DM, RR = 9.79 (95% CI: 7.14 to 13.43)].

CONCLUSIONS: There is a substantial public health burden related to PDR as it constitutes a major part of severe vision-threatening DR. Poor glycaemic control and its associated risk factors play an important role in the progression to PDR. Further research is required to elucidate epidemiological burden of PDR (specifically T1DM) and its associated risk factors.