Context Annual eye screening for patients with diabetes mellitus is frequently proposed as a measure of quality of care. However, the benefit of annual vs less frequent screening intervals has not been well evaluated, especially for low-risk patients.
Objective To examine the marginal cost-effectiveness of various screening intervals for eye disease in patients with type 2 diabetes, stratified by age and level of glycemic control.
Design Markov cost-effectiveness model.
Setting and Participants Hypothetical patients based on the US population of diabetic patients older than 40 years from the Third National Health and Nutrition Examination Survey.
Main Outcome Measures Patient time spent blind, quality-adjusted life-years (QALYs), and costs of annual vs less frequent screening compared by age and level of hemoglobin A1c.
Results Retinal screening in patients with type 2 diabetes is an effective intervention; however, the risk reduction varies dramatically by age and level of glycemic control. On average, a high-risk patient who is aged 45 years and has a hemoglobin A1c level of 11% gains 21 days of sight when screened annually as opposed to every third year, while a low-risk patient who is aged 65 years and has a hemoglobin A1c level of 7% gains an average of 3 days of sight. The marginal cost-effectiveness of screening annually vs every other year also varies; patients in the high-risk group cost an additional $40,530 per QALY gained, while those in the low-risk group cost an additional $211,570 per QALY gained. In the US population, retinal screening annually vs every other year for patients with type 2 diabetes costs $107,510 per QALY gained, while screening every other year vs every third year costs $49,760 per QALY gained.
Conclusions Annual retinal screening for all patients with type 2 diabetes without previously detected retinopathy may not be warranted on the basis of cost-effectiveness, and tailoring recommendations to individual circumstances may be preferable. Organizations evaluating quality of care should consider costs and benefits carefully before setting universal standards.
Diabetes mellitus is a leading cause of blindness in the United States.Randomized trials have clearly demonstrated that the risk of developing severe visual loss from proliferative diabetic retinopathy (PDR) and macular edema can be significantly reduced through the use of laser photocoagulation. Thus, screening, detection, and appropriate treatment of PDR and macular edema have the potential to significantly reduce the incidence of visual loss in patients with diabetes.
Screening is vital to preventing visual loss from diabetes because retinopathy is often asymptomatic early in the course of the disease. While no randomized trials have demonstrated that screening directly reduces rates of blindness, simulation models predict a reduction in visual loss with retinal screening. A number of previous cost-effectiveness analyses have demonstrated that, from a societal or governmental viewpoint, annual screening and treatment for PDR and macular edema are cost-effective interventions. As a result of these studies, provision of annual screening is being used as a measure of quality of care, with inclusion in Health Employer Data and Information Set (HEDIS) measures and other guidelines for diabetes care. While these guidelines have been widely disseminated, compliance has been disappointing, with annual screening rates generally ranging from 18% to 65% and broad-based population surveys suggesting rates of approximately 50%.
Previous analyses of screening for diabetic eye disease have not adequately examined the marginal benefits of increased screening frequency or specific methods of targeting patients. For example, it has been suggested that all patients with type 2 diabetes be screened at diagnosis and, if the result is negative, further screening be deferred for 3 to 4 years.Clinical predictors of diabetic retinopathy can also be used to effectively stratify the frequency of diabetic eye screening. For example, risk of retinopathy and eventual blindness can be stratified by level of glycemic control.Thus, we sought to evaluate whether hemoglobin A1c level can be used to effectively stratify the frequency of diabetic retinal screening and improve the efficiency and cost-effectiveness of screening.