Ocular Telehealth Initiatives in Diabetic Retinopathy - Springer Link

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a) Assure appropriate licensure and accreditation of all personnel; b) preserve HIPAA compliance ... software called Diabetic Retinopathy Assessment and.
Ocular Telehealth Initiatives in Diabetic Retinopathy Paolo S. Silva, MD, Jerry D. Cavallerano, OD, PhD, and Lloyd M. Aiello, MD

Corresponding author Jerry D. Cavallerano, OD, PhD Beetham Eye Institute, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA. E-mail: [email protected] Current Diabetes Reports 2009, 9:265–271 Current Medicine Group LLC ISSN 1534-4827 Copyright © 2009 by Current Medicine Group LLC

Diabetic retinopathy (DR) is a common complication of diabetes mellitus and a leading cause of new-onset vision loss in adults worldwide. Current medical and surgical evidence-based care, including laser photocoagulation, is effective in preserving vision. This care is most effective prior to the onset of ocular or visual symptoms, but many diabetic persons do not receive the recommended annual eye examination for the evaluation of the retina for level of DR. With diabetes incidence and prevalence increasing at epidemic rates and the prediction that 370 million people worldwide will have diabetes by the year 2030, human and fiscal resources will be unable to meet the visual needs with current acute care methods. Appropriate and validated telemedicine programs for DR hold the promise of both enrolling patients into appropriate eye care programs and, more importantly, providing more effective, high-quality diabetes eye care based on current and developing technology.

Introduction Current care and therapy are remarkably effective in preventing blindness and preserving vision for people at risk of vision loss from diabetic retinopathy (DR). Forty years of clinical trials, dating back to the landmark Diabetic Retinopathy Study (1971–1975) and the subsequent Early Treatment Diabetic Retinopathy Study (1979–1991), provide the evidence that established laser photocoagulation as the standard treatment for DR. Focal laser photocoagulation, as performed in the Early Treatment Diabetic Retinopathy Study (ETDRS), reduces the risk of moderate vision loss (a doubling of the visual angle; eg, 20/20 reduced to 20/40) by 50% or more over a 5-year period [1,2]. Scatter laser photocoagulation, as

fi rst demonstrated in the Diabetic Retinopathy Study (DRS) and further elucidated in the ETDRS, in conjunction with vitrectomy surgery, reduces the 5-year risk of severe vision loss (ie, best corrected visual acuity of 5/200 or worse) to less than 4% per eye and less than 2% per patient [3–5]. DR, therefore, is a leading cause of preventable new-onset vision loss. In addition to laser surgery for DR, major clinical trials have identified medical care that further reduces the risk of onset and progression of DR. The Diabetes Control and Complications Trial (DCCT), which enrolled 1441 patients with type 1 diabetes mellitus (T1DM) and with no or mild to early moderate nonproliferative diabetic retinopathy (NPDR), demonstrated that intensive control of blood glucose levels, as reflected in glycated hemoglobin (HbA1c) levels, significantly reduces the risk of onset and progression of DR [6]. In the primary prevention cohort, for those patients with no DR at baseline, intensive glucose control resulted in a 27% reduction in risk of onset of DR and a 78% reduction in risk of a three-step progression of DR. In the secondary progression cohort, for those patients with mild to early moderate NPDR at baseline, intensive control resulted in a 54% reduction in risk of a three-step progression of DR, a 47% reduction in risk of severe NPDR or proliferative DR (PDR), a 56% reduction in need for laser photocoagulation, and a 23% reduction in risk of diabetic macular edema (DME) [6]. The Epidemiology of Diabetes Interventions and Complications (EDIC) study, which continues to monitor 1211 of the 1441 patients enrolled in the DCCT, demonstrated that there is a prolonged beneficial effect of early intensive therapy that has continued at least 10 years after the conclusion of the DCCT [7–9]. This sustained legacy effect persisted despite virtual convergence of HbA1c levels of the intensive and conventional control groups. The United Kingdom Prospective Diabetes Study (UKPDS) measured the impact of intensive control of blood glucose levels, as reflected in HbA1c levels, on onset and progression of DR in patients with newly diagnosed type 2 DM (T2DM) [10]. In 4209 patients enrolled in the study, the UKPDS demonstrated that intensive glucose control resulted in a 17% reduction in two-step progression of DR, 29% reduction in need for laser photocoagulation, 23% reduction in rate of vitreous hemorrhage, and 16%

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reduction in onset of legal blindness [10]. Once again, the UKPDS demonstrated a legacy effect with a prolonged benefit of early intensive control that persisted beyond a period when the intensive and conventional group had virtually the same level of HbA1c [11]. Studies show that additional systemic conditions impact or are associated with onset and progression of DR [12]. These factors include hypertension, hypercholesterolemia, dyslipidemia, renal disease, anemia, abdominal obesity, and pregnancy [12–15]. Consequently, control of co-morbidities, in addition to intensive glycemic control, is a mainstay of diabetes eye care.

Rationale for Telehealth and Telemedicine for Diabetic Retinopathy The American Telemedicine Association (ATA) defines telemedicine as the use of medical information that is exchanged from one site to another via electronic communications to improve a patient’s health status. Telehealth encompasses a broader definition of remote healthcare that does not always involve clinical services, such as videoconferencing, transmission of images, remote monitoring of vital signs, continuing medical education, and nursing call centers [16]. DR is a disease that presents an ideal model for telemedicine and telehealth. A rigorous, standardized grading system of retinal images to determine DR severity level was validated by the ETDRS. Furthermore, diabetes mellitus is a common, complex, chronic disease that requires life-long care with careful follow-up. Diabetes has reached epidemic proportions, and its incidence and prevalence continue to grow. There are approximately 24 million Americans with diabetes as of 2009. There were 3 million new cases of diabetes diagnosed in the United States between 2005 and 2007, and an additional 57 million Americans have prediabetes. Presently, 25% of the US population age 60 years and older has diabetes [17]. Worldwide, the figures are just as staggering; in 2003, there were approximately 194 million people with diabetes, and that number is expected to climb to 370 million by the year 2030, a greater than 72% increase [18]. Diabetic retinal vascular abnormalities are present from the onset of diabetes, and overt DR is ultimately present in nearly all patients with 15 years or more of either T1DM or T2DM. It is the most common microvascular complication of diabetes and is the leading cause of new-onset adult blindness in the United States and other industrialized countries [19,20]. Evidence-based care is remarkably effective in preserving vision and preventing moderate and severe vision loss from DR, but many people with diabetes do not receive or have access to appropriate eye care [21–23]. Furthermore, DR is most amenable to sight-preserving treatments given prior to the onset of any visual symptoms or vision loss. Current practice recommendations generally advise annual retinal evaluation to determine the level of DR and appropriate eye and systemic care for all persons with diabetes [24–26].

Contemporary care for diabetic eye disease is based on regular eye examination for level of DR, timely and appropriate laser and surgical intervention, and systemic medical control. Eye evaluations to assess the level of DR should be performed at least annually and should become more frequent as eye disease progresses. Appropriate laser photocoagulation and vitrectomy surgery are performed promptly when indicated to reduce the risk for visual loss. Adequate control of blood glucose level and other systemic co-morbidities, such as hypertension and dyslipidemia, has been shown to delay onset and progression of DR. Providing eye care to the growing population worldwide with diabetes will inevitably exhaust the currently available resources. Consequently, novel approaches are needed to both provide access and deliver the eye care that is crucial to preserving vision in persons with diabetes. Ocular telemedicine for DR has the potential to provide people with diabetes both access to a program of regular eye care and an alternative method of delivering ongoing evidence-based eye care.

Validation of Telemedicine for Diabetic Retinopathy An effective telemedicine program for DR should apply the evidence-based care established over the past 40 years with the goals of preserving vision, reducing the risks of vision loss, extending access to care, and offering alternative methods of providing eye care. The ATA has established recommendations for telemedicine for DR with the intent of improving clinical outcomes and promoting informed and reasonable patient and care provider expectations [27••]. These practice recommendations address clinical, technical, and administrative components of remote care for DR and are summarized in Table 1, Table 2, and Table 3. Clinically, because ETDRS 30°, stereo, seven-standard fields, color 35-mm slides (ie, ETDRS photos) are the accepted standard for evaluating DR, the ATA guidelines accepted ETDRS photos as the benchmark criterion to assess the accuracy of a telemedicine system for DR against which telemedicine digital imaging systems have to be validated. The ATA defined four clinical categories of assessment of DR in its practice recommendations. Category 1 programs identify persons who have no or very mild NPDR (ETDRS level 20 or less) versus those with levels of DR worse than ETDRS level 20. Category 2 programs identify persons who have sight-threatening or potentially sight-threatening DR as evidenced by any level of DME, severe or worse levels of NPDR (ETDRS level 53 or worse), or PDR (ETDRS level 61 or worse) versus patients who do not appear to have sightthreatening DR. Category 3 programs are able to identify ETDRS-defined levels of NPDR (mild, moderate, severe), PDR (early, high risk), and DME with accuracy sufficient to determine appropriate follow-up and treatment strategies, which allows patient care and management to match clinical recommendations based on clinical retinal examination through dilated pupils. Category 4 programs match or exceed the ability of ETDRS photos to identify lesions

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Table 1. ATA guidelines summary: clinical categories of validation Category 1

Separates patients into two categories: a) those who have no or very mild nonproliferative diabetic retinopathy, and b) those with levels more severe than mild nonproliferative diabetic retinopathy

Category 2

Indicates a system that can accurately determine if sight-threatening diabetic retinopathy (as evidenced by any level of diabetic macular edema, severe or worse levels of nonproliferative diabetic retinopathy, or proliferative diabetic retinopathy) is present or not present

Category 3

Indicates a system that can identify Early Treatment Diabetic Retinopathy Study–defined levels of nonproliferative diabetic retinopathy (mild, moderate, or severe), proliferative diabetic retinopathy (early, high risk), and diabetic macular edema with accuracy sufficient to determine appropriate follow-up and treatment strategies

Category 4

Indicates a system that matches or exceeds the ability of Early Treatment Diabetic Retinopathy Study photos to identify lesions of diabetic retinopathy to determine levels of diabetic retinopathy and diabetic macular edema

ATA—American Telemedicine Association.

Table 2. ATA guidelines summary: technical considerations Image acquisition

Image data set must use DICOM standards and include DICOM image information in the image headers

Compression

Reversible and irreversible compression should undergo clinical validation for diagnostic accuracy

Data communication/transfer

Transmission should have no loss of clinically significant information, should be DICOM compliant and accompanied by a current DICOM conformance statement, and include error-checking capabilities

Archiving and retrieval

Storage should comply with facility, state, and federal regulations for medical record retention and be equivalent to policies for protection of hard copy storage media to preserve imaging records

Security

All systems must be HIPAA compliant

Reliability and redundancy

Images should be retained as part of patient’s medical record to meet clinical needs of facility and medical staff

Documentation

Reports of findings should be compliant to DICOM standard for structured reports

ATA—American Telemedicine Association; DICOM—Digital Imaging and Communications in Medicine; HIPAA—Health Insurance Portability and Accountability Act.

Table 3. ATA guidelines summary: operational and business elements Operational

a) Integrate ocular telehealth with primary care of diabetes consistent with accepted standards; b) preserve doctor–patient relationship, insure quality of images and image evaluation, and insure adherence to recommendations; c) insure appropriate communication and qualifications of personnel; d) provide appropriate system and data maintenance, security, integrity, and recovery

Legal/regulatory

a) Assure appropriate licensure and accreditation of all personnel; b) preserve HIPAA compliance for data privacy, integrity, security, retrieval, and patient consent; c) provide liability coverage through appropriate risk management and insurance; d) obtain patient consent emphasizing difference between comprehensive eye examination and telehealth program, and the benefits and risks of program; e) establish quality management, standardized training, ongoing evaluation, continuing education, and performance improvement

Financial

Establish program sustainability through a well-developed business plan

ATA—American Telemedicine Association; HIPAA—Health Insurance Portability and Accountability Act.

of DR to determine levels of DR and DME. Functionally, Category 4 validation indicates that a program can replace ETDRS photos in any clinical or research program. Clinical validation, therefore, is not dependent on the number of retinal fields imaged, field composition or size, image modality or display, image color, stereoscopic evaluation, or other elements of imaging provided the system matches ETDRS

photos to meet the criteria for one or more of the categories defined here. This measured approach to program validation for ocular telemedicine allows clear definition of both patient and practitioner expectations. In a review of the current literature, ocular telemedicine for DR was shown to be an accurate and reliable method, being highly sensitive and specific in the detection of DR and DME [28•].

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Twenty-First Century Telemedicine Programs for Diabetic Retinopathy There are multiple telemedicine programs for assessing DR. These programs vary in design and execution, but their underlying goal is the ability to extend diabetes eye care. Ideally, diabetes eye care should be integrated into a telemedicine program of total diabetes care. Diabetes telemedicine in the future may allow virtual continuous monitoring and care for diabetes that would include regulation of blood glucose levels, blood pressure, nutrition, exercise, and other elements of diabetes management [29]. Despite widespread and expanding use of ocular telemedicine for DR, only a limited number of programs have demonstrated validity in diagnosing level of DR according to ATA practice recommendations. These systems vary in the number of images required for examination, field defi nition, and other factors. This article does not attempt to provide a comprehensive review of ocular telehealth or telemedicine programs, but rather provide a brief sampling of programs that may be incorporated into a comprehensive telemedicine program for diabetic eye disease.

International programs Telemedicine programs for DR have been initiated in various countries worldwide. The Aravind Eye Care System in India conducted 2,396,100 outpatient visits and performed 285,745 surgeries from April 2007 to March 2008 [30]. The Aravind Eye Care System employs an ocular telemedicine program to give patients access to diabetes eye care by acquiring digital retinal images of diabetic patients at remote sites either from a mobile van or satellite clinic. The images are stored in specially designed software called Diabetic Retinopathy Assessment and Grading Over Network (DRAGON) that is designed to transmit images and patient data to a reading center at the Aravind Eye Hospital, where retinal specialists can interpret the images and grade retinopathy. The software allows the grader to diagnose the severity level of DR and suggest further management. In a study of 105 patients in the Aravind program, the overall agreement between clinical grading of DR and grading of images was 81.3%, and there was good agreement (κ = 0.77) between clinical examination and grading of images for patients with clinically significant DME, suggesting that the Aravind model is a valid tool to supplement clinic retinal examination and to detect sight-threatening DR [31]. Telemedicine programs for DR located at diabetologists’ offices or at screening camps are presently under evaluation in India. The Fundusnet Project was a telemedicine program for DR funded by the Spanish Agency Commission that ran from 1998 to 2000 to test telemedicine for detecting DR. Nonmydriatic images from 70 patients were acquired and transmitted to a reading center and graded for level of DR. The presence or absence of DR was correctly identified in all cases (κ = 1) and the results supported the Fundusnet as a suitable program to provide patients access to diabetes eye care and to detect the presence of DR [32].

United States programs The Vine Hill Study evaluated the impact of ocular telemedicine for DR on retinal examination rates in an inner-city primary care clinic [33•]. Patients in the clinic were offered either referral for ophthalmology examination or digital retinal imaging. Retinal imaging was performed using a Cannon CR6-45NM fundus camera and software (Digital Healthcare EyeQ Lite [Cannon, Lake Success, NY]) to manage digitized clinical information. Of the 495 patients offered the choice, 40.6% (n = 201) chose digital imaging at the clinic visit. Of the 59.4% (n = 294) choosing ophthalmologist examination referral, only 31.3% (n = 92) adhered to the recommendation for ophthalmologist examination. Sight-threatening DR was identified in 11% (n = 22) of the patients examined with digital imaging. The Inoveon Diabetic Retinopathy-3DT System (Inoveon, Oklahoma City, OK) captures ETDRS 30°, stereo, seven-standard fields, color digital images following pharmacologic pupil dilation. In a study of 290 adults with DM from the Chickasaw Nation’s Carl Albert Indian Health Facility in Ada, OK comparing Inoveon digital images with ETDRS seven-standard field photos recorded on 35-mm slides, digital imaging identified DR disease levels with a sensitivity of 98.2% and specificity of 89.7% compared with ETDRS photos [34]. In a study involving seven primary care settings, 2771 diabetic patients who reported no eye examination within the past year were imaged with a DigiScope (EyeTel Imaging, Columbia, MD) following pharmacologic pupil dilation. Seventy-two patients (3%) demonstrated vision-threatening eye pathology and 456 (16%) demonstrated non–visionthreatening ocular pathology. Despite pupil dilation, 304 patients (11%) had ungradable images, but the program demonstrated the value of retinal imaging for DR in the primary care setting for patients with diabetes who are otherwise not receiving recommended eye examinations [35].

The Joslin Vision Network diabetes eye care program The Joslin Vision Network diabetes eye care program (JVN) is an ATA category 3 program developed at the Joslin Diabetes Center. Early JVN programs were developed and deployed through a cooperative agreement with the United States Department of Defense and United States Veterans Administration (Cooperative Agreement DAMD 17-03020062). The JVN has served as a pilot program for the majority of the federally funded programs for ocular telemedicine for DR. The protocol and technology developed by the JVN continues to be used on all three major federal telemedicine programs for DR. The JVN follows a strict protocol for acquiring nonmydriatic retinal images and for grading and reporting the level of DR. The JVN has demonstrated ability to match ETDRS photos to identify lesions of DR and level of DR [36] and compares favorably with clinical examination to identify the level of DR [37,38]. A prospective study assessing the ability of the JVN to identify onset and progression of DR in patients with documented

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or minimal DR at their eye examination 11 or more months prior to imaging demonstrated that the JVN has potential to provide an alternative to dilated fundus examination to assess level of DR [39]. In another study, the JVN demonstrated excellent ability to identify nondiabetic eye conditions such as cataract, suspicion of glaucoma, retinal embolism, age-related macular degeneration, and choroidal nevus [38].

The Veterans Administration diabetes eye care program The US Veterans Administration has committed to the use of telemedicine for assessing DR, with the goal of assessing 75,000 patients per year [40••]. The US Veterans Administration and Joslin Diabetes Center deployed a JVN program at the Togus VA Medical Center in 2001 [41]. In one year 1219 diabetic patients were imaged in the outpatient clinic, thereby extending access to diabetes eye care to these patients. Of these patients, 908 had no DR or mild NPDR, and the JVN program potentially would be able to provide diabetes eye care to this group of patients. In another study conducted at the VA hospital in Boston, MA, imaging with the JVN improved adherence to recommended annual eye examination in patients who had retinal imaging (n = 223) compared with those who did not have retinal imaging (n = 225 [87% vs. 77%; P < 0.01]), demonstrating the value of telemedicine in increasing access to diabetes eye care [42]. The US Veterans Administration has subsequently developed an independent telemedicine program for DR modeled on the JVN to both enroll patients into a care program for DR and to provide retinal assessment for DR when appropriate.

The Indian Health Service diabetes eye care program The United States Indian Health Service (IHS) provides medical care for 1.9 million Native Americans and Alaska Natives living on or near reservations. Native Americans and Alaska Natives have the highest rates of T2DM in the United States. The Phoenix Indian Medical Center, operated by the IHS, provides health care services without out-ofpocket health care expense to eligible Native Americans and Alaska Natives. When the JVN program was initiated in the primary care setting at Phoenix Indian Medical Center, the rate of annual DR surveillance was approximately 50%. The rate increased to 75% over a 4-year period, representing a 50% increase in examination rate. During this same period, the rate of sight-preserving laser treatment increased from 19.6 per 1000 patients to 29.5 per 1000, representing a 51% increase in laser treatment rate and reflecting the value of telemedicine in providing patients access to sight-preserving care [43]. Presently, there are more than 70 JVN telemedicine sites deployed in the IHS.

The United States Department of Defense diabetes eye care program The United Sates Department of Defense has deployed telemedicine programs for DR at a number of facilities. Record review of 243 patients who had nonmydriatic retinal imaging at four Walter Reed Health Care System facilities in metropolitan Washington, DC revealed that 35% of the

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images were not fully gradable for level of DR. For images that were gradable, however, there was an 86% agreement for diagnosis of level of DR using nonmydriatic retinal imaging compared with subsequent dilated fundus examination. In gradable images, the overall sensitivity of the nonmydriatic imaging was 98% and specificity was 100% for grading the level of DR within one level of dilated fundus examination; agreement for DME, which was present in six eyes, was 100% [44]. In a modeled economic analysis of a digital ocular telehealth program for DR in three US federal agencies (the Department of Veterans Affairs, the Department of Defense, and the IHS) for the detection of PDR, comparison of nonmydriatic ocular telemedicine using a JVN program versus traditional clinic-based retina examination with ophthalmoscopy after pupil dilation showed that the JVN program was the overall dominant strategy, being less costly and more effective in most cases than fundus examination through dilated pupils [45].

Future of Diabetes Ocular Telehealth Programs Current telehealth programs for DR have enormous potential for the preservation of vision and the prevention of visual loss from diabetes. The continued growth of diabetes ocular telehealth programs should rely on the advancement of three critical technological aspects: 1) portable imaging devices providing high-quality images; 2) automation of lesion detection, image analysis, treatment planning, and reporting; and 3) identification of new prognostic features on retinal images. Inexpensive, easy-to-use, portable imaging devices that local health care workers can be trained to use should be developed and validated in terms of sensitivity and specificity [46]. The sensitivity and specificity of new imaging systems that are developed should meet or exceed currently accepted standard photographic systems. Systems with low sensitivities would mean patients with DR will be wrongly assured that they do not have the disease and systems with low specificities or poor image quality would cause a higher percentage of unnecessary referrals, causing an undue burden on the ophthalmologist and anxiety on the part of the patient. Development of portable nonmydriatic cameras, scanning laser ophthalmoscopes, and other imaging modalities has the potential to address this need [47]. The goal of automation of retinal image analysis has long been studied. Excellent reviews on this topic have been published [44,49]. Diabetes telehealth programs that have implemented such methods have shown a significant decrease in the burden of manual retinopathy evaluation [50,51]. Programs have reported fairly high sensitivities of 88% to 93%, but functionality has been limited by relative low specificities ranging from 53% to 71% [50,51]. Two recently published reports have shown promise in this field. The first report uses an information-processing paradigm called an artificial neural network and reports sensitivity of 90% and specificity of 100% in the identification of no

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DR, NPDR, and PDR [52]. The second report utilizes a novel image-analysis method that employs content-based image retrieval and has reported specificity of 92% to 94%, allowing statistically relevant predictions regarding the presence and severity of DR [53]. Both systems have yet to be tested in an actual diabetes telehealth program. Lastly, with the integration of patient systemic medical information and retinal images, ocular telehealth programs should focus on research investigating correlations between a patient’s systemic condition and prognostic features of the retinal images. Early work on this integration is currently being done in children with diabetes using the JVN in a program at the Hospital de Niños JM de los Rios in Caracas, Venezuela. The early results suggest increasing retinal vessel stress among patients with poor glycemic control. These early retinal changes prior to the onset of overt retinopathy are consistent with retinal electrophysiologic changes that have been described in clinical studies [54•]. Further research in this area will provide better insight on the pathologic process behind DR and enable detection of features that would predispose patients to a greater risk for progression or warrant earlier treatment.

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Conclusions Ocular telemedicine for diabetes eye care has the potential to extend evidence-based eye care to persons not presently receiving such care and can provide an alternative method of assessment and care under defined circumstances. With the diabetes epidemic already overwhelming our ability to provide early sight-preserving care to diabetic persons, ocular telemedicine for DR will become a necessity and likely a mainstay of diabetic eye care. Programs, however, must be validated to match established standards of care and ideally should integrate total diabetes care into the programs. The immediate near-term focus should be on the development of portable, low-cost, quality image-acquisition devices, and the mid-term focus should be on automated image analysis and research on unique prognostic features on retinal images.

Disclosure No potential confl icts of interest relevant to this article were reported.

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