Prevalence of diabetic retinopathy among 13473 patients with diabetes mellitus in China: a cross-sectional epidemiological survey in six provinces

OBJECTIVE: To describe the prevalence and severity of diabetic retinopathy (DR) and sight-threatening DR (STDR) among Chinese adults with diabetes. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional epidemiological survey across Mainland China (N=13 473). Participants were diagnosed with diabetes mellitus by physicians and transferred to our screening clinics (1/3 from hospital patients, 1/3 from city residents, the other 1/3 from rural residents). 2 fundus photographs were taken of each eye with a colourful, non-mydriatic and non-stereoscopic camera and were graded according to the UK guidelines. MAIN OUTCOMES AND MEASURES: The prevalence and severity of DR and STDR. RESULTS: Of the 13 473 participants with diabetes participating in the study, 4591 had DR and 1769 had STDR, for an overall prevalence of 34.08% (95% CI 33.28% to 34.88%) and 13.13% (95% CI 12.56% to 13.70%), respectively. Among these, gradable photographs were available for 12 780 participants (94.86%). Participants who were aged >65 years were less likely to suffer from DR or STDR (p<0.001; age distribution). No gender-related differences were present (p>0.05). Participants with STDR suffered from more severe visual impairment compared with those without STDR (p<0.001). The prevalence of DR and STDR in the northern region was higher than in the southern region (p<0.001). The prevalence of DR was closely related to duration of disease (OR 2.63; 95% CI 2.42 to 2.86; p<0.001) and diabetes onset age (OR 0.38; 95% CI 0.35 to 0.41; p<0.001). CONCLUSIONS: The prevalence of DR and STDR in Mainland China appeared a little high, and varied according to area. Non-proliferative DR was more common, but STDR needed prompt treatment, especially in economically less developed areas. This study highlights the necessity for DR screening and treatment in Mainland China.