Abstract

The purpose of this study was to compare the effectiveness, costs and benefits of screening for diabetic retinopathy with retinal photography and with ophthalmoscopic examination in health care centres by primary care physicians, and also to study the quality of life and mortality of visually impaired diabetics. There are about 150000 diabetics in Finland. There were 881 visually impaired persons due to diabetic retinopathy in the Finnish Register of Visually Impaired Patients in 1994 (1122 in 1997). Laser photocoagulation has proved to be an effective treatment in diabetic retinopathy preventing visual loss. The screening methods are ophthalmoscopic examination and retinal photography.

The incidence of retinopathy was calculated from the photogaphy screening in the Oulu Health Care Centre in 1987 (N = 1015), in 199192 (N = 1844) and in 199394 (N = 1484). The ophthalmoscopy screening was studied from patients records (N = 242) in the Raahe Health Care Centre. Out of 120 visually impaired persons with diabetic retinopathy in the province of Pohjois-Pohjanmaa, 50 were interviewed by the health care secretary. The study included cost-benefit analysis for the costs of screening and treatment of diabetic retinopathy compared with the costs of visual impairment. Furthermore the quality of life of patients with visual impairment due to diabetic retinopathy was studied using the Nottingham Health Profile questionaire (NHP) and compared with diabetic patients without visual impairment. The mortality rate of visually impaired patients was compared to that of diabetic retinopathy patients who had been treated with laser photocoagulation.

The incidence of all diabetic retinopathy was 9.4 per cent per year and 2.8 per cent per year for moderate to severe retinopathy, and in patients with no insulin in their treatment the incidence of all retinopathy was 3.0 and 1.2 per cent per year respectively. The screening costs per diabetic person screened were 148 Finnish marks (FIM) in the photographic method and 68 FIM in the ophthalmoscopic method. It was calculated that 156 visual impairment cases could be prevented per year in Finland with the photographic method. The screening and treating costs in finding one preventable case of visual impairment were 185000 FIM. The costs of visual impairment were 594000 FIM per patient. So retinal photography screening and treatment of diabetic retinopathy could lead to savings of 63.9 million FIM per yearly screening in Finland.

The quality of life of visually impaired persons was worse than that of other diabetics in two dimensions of the NHP, Energy and Mobility. In the second part of the NHP, the quality of life of visually impaired persons was worse than that of other diabetics in all questions except working. The mortality rate of visually impaired persons, 14.5 per cent per year was twice as high as that of diabetic patients treated with laser photocoagulation.

The incidence of diabetic retinopathy in Finland was about the same as in other industrialized countries. Retinal photography seemed to be a cost-effective screening method for preventing visual impairment and the cost benefit ratio of screening and treating diabetic retinopathy was 3.2. The quality of life of visually impaired patients was worse and mortality risk higher than that of other diabetics.