The Cost‐Effectiveness of Three Screening Alternatives for People with Diabetes with No or Early Diabetic Retinopathy

Diabetic retinopathy (DR)—a complication involving the retinal microvasculature resulting in damage to the retina from ischema, neovascularization, hemorrhage, and edema—develops in virtually all people with diabetes mellitus and can progress to more advanced stages threatening permanent visual impairment and blindness (American Academy of Ophthalmology Retina Panel 2008). In 2004, DR was the estimated cause of 195,000 prevalent cases of visual impairment and blindness in the United States (The Eye Diseases Prevalence Research Group 2004). Screening to increase detection of DR progression and timely treatment can reduce the risk of permanent visual impairment. Based on clinical and cost-effectiveness evidence from the 1990s, the American Academy of Ophthalmology (AAO), the American Optometric Association, and the American Diabetes Association currently all recommend annual dilated evaluations by an eye-care professional (annual eye evaluations) for all patients with diabetes (Dasbach et al. 1991; Javitt et al. 1994; Javitt 1995; Javitt and Aiello 1996; Fodera 1999; Fong et al. 2003; American Academy of Ophthalmology Retina Panel 2008). This recommendation is likely most cost-effective for patients with advanced DR or elevated hemoglobin A1c (HbA1c) levels, but annual evaluation may be costly for those with no DR or with microaneurysms (MA) only. For lower-risk patients with diabetes, Vijan, Hofer, and Hayward (2000) found that less frequent evaluations provide nearly equivalent benefits as annual ones at lower costs (Vijan, Hofer, and Hayward 2000). In 2006, nearly 9.1 million Americans had type 2 diabetes with limited or no signs of DR (National Center for Health Statistics 2005–2006). After accounting for the rate of compliance with current screening recommendations and the costs of evaluation by an eye-care professional, a change from annual evaluations to biennial evaluations could save approximately U.S.$200 million in health expenditures annually with limited risks to health. However, Vijan, Hofer, and Hayward (2000) did not account for noncompliance with recommendations or for the benefits of detecting other ocular disorders. These limitations may have influenced their results because only 64 percent of people with diabetes aged 30 or older comply with current recommendations and because people with diabetes are at higher risk for incident glaucoma, cataract, and possibly vision-threatening age-related macular degeneration (AMD) than people without diabetes (Klein et al. 1995; Bonovas, Peponis, and Filioussi 2004; Clemons et al. 2005; National Center for Health Statistics 2005–2006). Furthermore, advocates for annual evaluation argue that the annual recommendation is easier to communicate, creating less risk of noncompliance. Over the past decade, retinal digital photography (telemedicine) has emerged as a lower cost alternative to annual evaluation by an eye-care professional. Telemedicine uses digital retinal photography to enable screening in nonophthalmologic settings. Images are electronically transferred to a grading center for evaluation, and patients with evidence of mild to severe DR are referred to an eye-care professional for a full evaluation. Telemedicine has shown better sensitivity (98 percent) and specificity (86 percent) in detecting DR than ophthalmoscopy (Moss et al. 1985; Ahmed et al. 2006) and usually costs less from both the health care and societal perspectives than dilated eye examinations because of lower provider reimbursements and lower patient productivity losses from time lost to treatment. Because 82 percent of people with diabetes visit a primary care provider annually, telemedicine could also potentially increase the annual probability of screening for DR compared with clinical eye evaluations (National Center for Health Statistics 2005–2006). Unfortunately, telemedicine currently has a limited ability to detect prevalent eye conditions other than AMD, such as cataract, glaucoma, or uncorrected refractive error (URE, a presenting acuity of 20/40 or worse that can be easily corrected with glasses or contact lenses). The much greater ability of clinical eye evaluation to detect these conditions may result in either annual or biennial evaluation being more cost-effective than telemedicine. We designed this study to provide additional information regarding the most cost-effective screening alternatives for people with diabetes who are at low risk of progression when accounting for imperfect compliance with screening recommendations and the ability of eye evaluation to detect other common visual disorders. We estimated the cost-effectiveness of four possible methods of managing this patient population: patient self-referral following visual symptoms, annual eye evaluation, biennial eye evaluation, and annual telemedicine screening in primary care settings. Our results can be used to evaluate the management practice that is most likely to be cost-effective at different societal valuations of the gains from medical therapy and to inform what additional research may be required to update recommendations.