Purpose  To assess frequency and associated factors of progression of diabetic retinopathy (DR) in subjects with known diabetes in a population-based setting.

Methods  The Beijing Eye Study is a population based study performed in Greater Beijing in 2001 and 2006. The present investigation included all subjects with known diabetes mellitus in 2001, who participated in the follow-up examination in 2006. Fundus photographs were assessed. 

Results  The study included 170 subjects; 119 (70%) subjects showed no signs of DR in 2001, 43 subjects had mild nonproliferative DR, 4 subjects had moderate nonproliferative DR, and 4 subjects had proliferative DR. Re-examined in 2006, 36 (21.2%) subjects (18 subjects with DR present at baseline, 18 subjects with newly diagnosed DR in 2006) showed a progression of DR during follow-up. In the 51 subjects with DR at baseline, 18 (35.3%) subjects demonstrated a progression of DR. Progression of DR was associated with rural region (Odds ratio (OR):5.43) and self-reported arterial hypertension (OR: 3.85). In the non-progressive subgroup, presence of DR was associated with low educational level (OR:0.30), treatment modes of diabetes mellitus (OR:10.24) and cataract surgery (OR:9.14). 
Conclusions  In a population-based setting in Greater Beijing, progression of DR occurred in 35% of subjects with pre-existing DR and overall in 21% of subjects with known diabetes within a 5-year period. Progression of DR was significantly associated with rural region and self-reported arterial hypertension. In the stable subjects, presence of DR was significantly associated with poor educational level, insulin treatment of diabetes and cataract surgery.