ABSTRACT
Objective To observe the effect of long-term intensive glucose control therapy on diabetic retinopathy in outpatients with type 2 diabetes mellitus.Methods Forty-nine patients with type 2 diabetes mellitus were randomly assigned to participate in the trial from 2002 to 2007,receiving either intensive (24 cases) or standard glucose control (25 cases).The patients were examined by the same ophthalmologists to identify any new diabetic retinopathy (DR).After 5 years of intensive glucose control,all of the patients were asked to attend our clinic every 6 months,but no attempts were made to maintain their previously assigned therapies.Hemoglobin A1c (HbA1 c) was measured regularly.In November of 2009,a retinal examination was carried out by the same ophthalmologist who worked in the trial.The visual acuity,lens,vitreous body and fundus were examined after pupil dilation to identify diabetic retinopathy (DR).Fundus fluorescein angiography and retinal laser photocoagulation were carried out when necessary.Results In the second year after enrollment in the trail,the median HbA1c level of the intensive-therapy group was significantly lower than that of the standard-therapy group [(6.3 ± 0.6) ％ vs.(7.2 ± 1.2) ％,t =2.09,P ＜ 0.05],and was maintained in a controlled level throughout the following 4 years.During the post-trial monitoring,no new case of of macula edema or diabetic associated blindness occurred in either intensive or standard-therapy group,the whole occurrence of micro-aneurysms,fundus hemorrhage,as well as those who needed retinal laser photocoagnlation and lowering in visual acuity in intensive-therapy group was lower than that in the standard-therapy group (3 vs.14,1 vs.7,2 vs.4,3 vs.11,respectively ;9 vs.36,totally,x2 =4.719,P ＜ 0.05).During the first post-trial monitoring,there was no difference in median HbAlc level between intensive-therapy group and standard-therapy group [(7.2 ± 1.1) ％ vs.(7.3 ± 1.3) ％,t =0.25,P =0.806],which was sustained in the following years.In the trail,no new case of fundus hemorrhage or diabetic associated blindness occurred in intensive-therapy group during the five-year period of therapy.Number of new episodes of micro-aneurysm,macula edema were less in intensive-therapy group than that in standard-therapy group,number of new episodes of lowering in visual acuity,and those who needed retinal laser photocoagnlation,were significantly less in intensive-therapy group than that in standardtherapy group(15 vs.25,4 vs.23,Z =-4.459,P ＜ 0.05) during five-year follow-up.Conclusions The benefit of reduced incidence of diabetic retinopathy in intensive glucose can be maintained because of the legacy effect.