Payment Reform Needed to Address Health Disparities of Undiagnosed Diabetic Retinopathy in the City of Chicago

Introduction The Affordable Care Act (ACA) has expanded health coverage for thousands of Illinois residents. Expanded coverage, however, does not guarantee appropriate health care. Diabetes and its ocular complications serve as an example of how providers in underserved urban areas may not be able to keep up with new demand for labor- and technology-intensive health care unless changes in reimbursement policies are instituted. Methods A retrospective cohort study was conducted using medical encounter information from the Chicago HealthLNK Data Repository (HDR), an assembly of non-duplicated and de-identified patient medical records. We used a method of estimating the geographic distribution of undiagnosed diabetic retinopathy in the city of Chicago to illustrate the magnitude of potentially preventable eye disease. All rates were calculated for all ZIP Codes within Chicago (Cook County), and statistical differences between observed and geographically adjusted expected rates (p < 0.10, p < 0.05, p < 0.01) were highlighted as underserved areas. Results This analysis included 150,661 patients with diabetes identified from a total of nearly two million patients in Chicago. High rates of undetected diabetic retinopathy were found in low-income and minority areas. Within these areas, 37% of the identified diabetics were uninsured, with rates ranging widely from 20% to 68.6%. Among those with insurance, 32.8% were covered by Medicare and only 10% by Medicaid. Most patients with untreated diabetic retinopathy were found to reside in areas where primary health care is provided through Federally Qualified Health Centers. Conclusions With 150,661 diabetics identified in the city of Chicago, and this number continuing to rise each year, a manpower approach with ophthalmologist screening for diabetic retinopathy is not realistic. The ability to identify the growing number of diabetic patients with retinopathy in low-income areas will likely require the adoption of cost-effective screening technologies that are currently not funded by Medicare and Medicaid.

Results: This analysis included 150,661 patients with diabetes identified from a total of nearly two million patients in Chicago. High rates of undetected diabetic retinopathy were found in low-income and minority areas.

INTRODUCTION
As a result of the Affordable Care Act (ACA), thousands of Illinois residents are now able to receive health insurance and medical care.
Estimates of increased health coverage for Illinois parallel those of other states, with a 17% increase in Medicaid recipients from July 2013 to December 2015 [1]. Large metropolitan areas such as Chicago are likely to notice the greatest impact in new patients, since they have a substantial number of previously uninsured individuals. Chicago is the third largest city in the United States, with a population of over 2.7 million, among which more than 20% are uninsured [2]. Although an increasing number of minorities in selected areas of Chicago will now be enrolled in Medicaid, this may not guarantee access to care or appropriate referral to specialists, simply due to an insufficient number providers who accept this form of insurance [3]. The lack of resources common in underserved urban areas may also impede the use of labor-and technology-intensive screening interventions. The situation among patients with diabetes and its complications may serve as an example to facilitate a better understanding of how large numbers of patients in underserved areas are affected by these phenomena.
Persons with diabetes are at risk for diabetic eye disease, most importantly diabetic retinopathy. Among those with diagnosed diabetes, the prevalence of diabetic retinopathy is 9.9% [5], which translates to over 4.4 million Americans aged 40 years and older [4]. If undetected or untreated, diabetic retinopathy can lead to blindness. Timely detection and treatment, however, substantially reduces the risk of visual loss [6].
Vision loss and blindness are preventable in many diabetics if appropriate and accessible screening and medical care are available. It is understandable, therefore, that low-income and minority populations (often uninsured) are at greater risk of diabetic eye disease than the general population [7][8][9]. Compared to whites, African Americans have a higher incidence of diabetic retinopathy (38.8% vs. 26.4%) and vision-threatening diabetic eye disease (9.3% vs. 3.2%) [10]. Research has shown that the risk of vision loss due to diabetic retinopathy can be reduced with early detection and treatment; however, diabetic retinopathy remains the leading cause of new cases of legal blindness in persons between the ages of 20 and 74 [10].
The purpose of this study was to estimate the geographic distribution of undiagnosed diabetic retinopathy among residents of the city of Chicago using a city-wide health data repository for pre-ACA years 2006-2012. Targeting areas with the greatest health care disparities for diabetic eye care should help in formulating policies that optimize limited resources.

Study Design
A retrospective cohort study was conducted using medical encounter information from the Chicago HealthLNK Data Repository (HDR), an assembly of non-duplicated and de-identified patient medical records. The HDR includes nearly six million unique patients, of which nearly 2.7 million reside in Chicago [11]. These data are restricted to adults aged 18-89 years, and contain primarily structured data elements.

RESULTS
This analysis included 150,661 patients with diabetes identified from a total of nearly two million patients in Chicago. Figure 1  were superimposed on the map as green dots. These FQHCs predominately serve minorities and the uninsured patients. As shown in Fig. 1, (eye surgery, laser, and medications) [29], disparities in diabetic eye care still exist.
One of the goals of the Healthy People 2020 initiative is to reduce visual impairment related to diabetic retinopathy [30]. To this end, the National Eye Institute's 2012 strategic plan includes ''expand[ed] efforts in telemedicine to manage retinal diseases like diabetic retinopathy…via web-based networks'' [31].
Research has shown that telemedicine increases access to specialists for populations in rural and/or underserved areas, at a considerable cost savings [32]. Among the many facets of telemedicine is teleophthalmology, which includes retinal fundus examination. While a dilated eye exam with an eye care provider is considered the ''gold standard'' for detecting diabetic retinopathy, an alternative-but equally effective-method of diabetic eye disease screening is through a digital photograph of the retina.
Digital retinal photography with a non-mydriatic (undilated pupil) camera can be completed in about a minute's time by clinic support staff during a primary care visit, and then viewed online remotely by an ophthalmologist. Studies have shown that digital photography is as effective as a dilated eye exam, and patients with vision-threatening disease can be rapidly identified and promptly referred for examination and management [32,33]. The broad range of telemedicine technologies and protocols for diabetic retinopathy reflects progressive improvement in diagnostic sensitivity and specificity, with enhanced cost-effectiveness [34,35]. The operational and clinical components of telemedicine programs for diabetic retinopathy were recently reviewed, and the logistical advantages of such programs were consistently acknowledged [33,34]. Another limitation is that the HDR does not capture all practices and is not a sample of the entire city. Our map only allowed us to examine geographic statistical areas in the pre-ACA era. We could not account for eye care provided outside the FQHC, though that likelihood is low given the traditionally larger out-of-pocket costs for private screening in both the pre-and now post-ACA era.

CONCLUSIONS
Our study shows that in Chicago, a large proportion of unscreened patients with diabetes have undiagnosed diabetic retinopathy. The ability to screen the growing number of patients with diabetes in low-income areas will likely require adoption of cost-effective screening technologies. This in turn will be contingent upon Medicare and Medicaid payment reform that incentivizes the use of validated screening techniques [32,33]