Snapshot of Teleretinal Screening for Diabetic Retinopathy at the West Los Angeles Medical Center

Abstract

Introduction: The West Los Angeles Veterans Affairs Medical Center is a large urban facility with a robust teleretinal screening program in primary care clinic, established in 2006. The purpose of this article is to provide a snapshot of teleretinal screening at this site. Methods: Diabetic patients from 2012 were analyzed with a prospective cohort study. Demographic information, results of teleretinal screening, referral to eye clinic, and loss to follow-up (defined as no eye care within 2 years) were collected. Results: Of 516 patients with diabetes screened with teleretinal imaging, 120 patient charts were reviewed for data analysis. Teleretinal imaging diagnosed 15% (18/120) of patients with varying stages of nonproliferative diabetic retinopathy (DR). Of patients screened, 55.8% (67/120) of the patients were referred to an eye clinic for further ophthalmic evaluation. Nondiabetic retinopathy reasons for eye clinic referral included glaucoma suspect (13.3%, 16/120) and age-related macular degeneration (10.0%, 12/120). Of all patients screened, 37.5% (45/120) of them were lost to follow-up, defined as no teleretinal screening or eye clinic appointment within 2 years. Patients who lived farther away from clinic had a higher risk of loss to follow-up (p = 0.04). Discussion: We found, although only 15% of patients were diagnosed with DR from teleretinal screening, more than 50% of patients were referred to eye clinic. In addition, of all screened patients, there was a high rate of not returning to the Veterans Affairs (VA) for eye care.

Introduction

Diabetes mellitus (DM) is a chronic disease of epidemic proportions that affects 29 million people in the United States and 350 million people around the world.¹ Consequently, diabetic retinopathy (DR) is the leading cause of blindness in working aged individuals (20–59 years of age).^2,3 In the United States, 40% of patients with DM have some form of DR.⁴ Twenty years after diagnosis, more than 90% of patients with type 1 DM and more than 60% with type 2 DM have some degree of DR.^2,3

Current screening protocols are jointly recommended by the American Academy of Ophthalmology and American Diabetes Association.⁵ Screening is important because with timely management, treatment of DR is 90% effective at reducing the likelihood of severe vision loss.^6
–8 Patients with type 1 DM are recommended to initiate screening 3–5 years after diagnosis and then yearly thereafter. Patients with type 2 DM are recommended to initiate screening at the time of diagnosis and then yearly or every 2 years thereafter. Despite these guidelines, only about 60% of diabetic patients are estimated to have eye screenings as recommended.^9,10

Teleretinal screening has been an important measure to increase adherence with screening guidelines.^11,12 Teleretinal screening in lieu of a traditional dilated examination by an eye care provider can increase compliance with DR screening recommendations from 56% to 94%.¹³ Color fundus cameras are placed in primary care clinics so that patients do not need an additional ophthalmology or optometry appointment. These measures are helpful because in some areas of the country, there are an insufficient number of eye care providers to perform a dilated fundus examination on every diabetic patient annually. In addition, seeking eye care can be a sizeable barrier for patients with DM who are often overburdened with diabetic self-care and multiple specialty visits.

A sustainable teleretinal screening program for DR has been demonstrated by the Veterans Affairs Medical Centers (VAMCs) since 2006. The VAMCs form the largest integrated network of patients in the United States. The VAMCs have exclusively used a centralized electronic medical record system since 1997, providing a convenient way to upload and read images. VAMCs in Boston, Atlanta, and Portland have previously reported on different aspects of their teleretinal screening program.^9,14,15 These studies demonstrated increased compliance with screening recommendations, accuracy of screening, and increased eye clinic resource burden due to screening.

The purpose of this study was to provide a snapshot of teleretinal screening results at the West Los Angeles VAMC. Specifically, we focused on diagnosis made from teleretinal screening, referral rates, and loss to follow-up.

Methods

This study was a prospective cohort study conducted with Institutional Board Review approval from the West Los Angeles VAMC. Patients from 2012 were identified using teleretinal stop codes from the VAMC. Stop codes are identifiers constructed by the Veterans Health Administration for the purpose of collecting workload data. The first 10 patients per month were sampled for chart review.

Diabetic patients without evidence of eye care were referred to teleretinal screening by their primary care physician. Images were obtained at the primary care clinic by an experienced and certified ophthalmic technician. At least six images per eye were taken without dilation with a TRC-NW8 nonmydriatic camera (Topcon, Oakland, NJ). Images were read by a certified ophthalmologist and a report was entered into the patient's electronic medical record. A letter was generated and mailed to the patient's house by the certified ophthalmic technician. The letter included the patient's diagnosis, recommended follow-up time, and phone number to call for a follow-up appointment. The findings themselves were not specified.

Demographic information, including age, gender, and ethnicity, was collected. The distance from the eye clinic to patient's reported home address was calculated using home zip codes and Google Maps™. Hemoglobin A1c closest to the day of the teleretinal screening encounter was recorded.

Results of teleretinal imaging reports were collected, including whether any teleretinal images of a patient were of ungradable quality, detection of DR in either eye, and whether a referral to eye clinic was made. For patients who went to eye clinic, whether they had optical coherence tomography (OCT) imaging and the reason for OCT imaging were recorded. Loss to follow-up, defined as no eye care within 2 years, was examined in the entire cohort.

Data were collected and managed in Excel (Microsoft, Redmond, WA). Statistical analysis was performed using the statistical program R (R Foundation for Statistical Computing, Vienna, Austria). A logistic regression analysis was performed on the binary distributed data of loss to follow-up as a function of distance from home to clinic and diagnosis of DR and hemoglobin A1c. All data were found to be normally distributed using the Shapiro–Wilk normality test. Statistical significance was determined at α = 0.05 and all analyses and graphs were performed and created using the statistical program R.

Results

There were 516 patients examined through teleretinal screening in 2012 from the Primary Care Clinic at West Los Angeles VAMC. One hundred twenty were included in this cohort for analysis. The average patient age was 65 years and 117 patients were male (97.5%). Ethnicities were white (44.2%), African American (21.7%), Hispanic/Latino (13.3%), Asian (2.5%), and others (18.3%). The average distance from home to eye clinic to receive care was 107 miles. Forty-three percent (51/120) of patients travelled more than 50 miles to receive teleretinal screening.

Five percent (6/120) of the teleretinal images were ungradable. Teleretinal imaging diagnosed 15% (18/120) of patients with varying stages of nonproliferative DR. There was no proliferative DR diagnosed on teleretinal screening. Of patients screened, 55.8% (67/120) of them were referred to eye clinic. Nondiabetic retinopathy reasons for eye clinic referral included glaucoma suspect, age-related macular degeneration, and other reasons are listed in Table 1. Of patients referred, 76.1% (51/67) made it to eye clinic and the remaining 23.9% (16/67) did not follow up with eye clinic. Of those patients who were not referred, 39.6% (21/53) had at least one follow-up appointment with eye clinic.

Table 1.

Findings from Teleretinal Imaging

Diabetic retinopathy	15.0% (18)
Glaucoma suspect	13.3% (16)
Age-related macular degeneration	10.0% (12)
Choroidal nevus/CHRPE	4.2% (5)
Epiretinal membrane	3.3% (4)
Optic nerve pallor	1.6% (2)
Cataract	1.6% (2)
Retinal detachment	0.8% (1)
Other—pt requested glasses	3.3% (4)
Other—pt requested eye examination	2.5% (3)

CHRP congenital hypertrophy of the retinal pigment epithelium.

Of the individuals who were referred to eye clinic and went, 27.4% (14/51) had an OCT. OCT was taken for glaucoma suspect (four patients), cataract management (two patients), diabetic macular edema (two patients), and other retinal diseases (six patients). Of all patients screened, 37.5% (45/120) had no follow-up teleretinal screening or eye clinic appointment within 2 years.

Patients who lived further away from clinic had a higher risk of not returning to the Veterans Affairs (VA) for eye care (p = 0.04). A higher hemoglobin A1c value correlated to detection of DR (Table 2).

Table 2.

Results of Teleretinal Screening and Hemoglobin A1c

PATIENTS	% (n)	AVERAGE HgA1c	p
Without DR	86.7 (104)	7.2	<0.001
With DR	13.3 (16)	9.4

DR, diabetic retinopathy.

Discussion

This study analyzed teleretinal screening for DR at the West Los Angeles VAMC in 2012, ∼6 years after the program's inception. We found, although only 15% of patients were diagnosed with DR from teleretinal screening, more than 50% of patients were referred to eye clinic. Nondiabetic retinopathy referral reasons included glaucoma suspect and age-related macular degeneration. In addition, of all screened patients, there was a 37.5% rate of loss to follow-up, defined as no eye care within the next 2 years.

The purpose of teleretinal screening at the VAMC is to detect referral, warranting DR and intervene before vision loss occurs. In this study, any level of DR was referred to eye clinic and nonproliferative DR was detected in 15% of patients from teleretinal screening. Not surprisingly, increased hemoglobin A1c was highly correlated (p < 0.001) with the detection of DR. This underscores the relevance of glycemic control in the process of image grading. In our teleretinal reading protocol, recent hemoglobin A1c is collected as a data point for the image grader to be aware of. Given the importance of blood pressure control in the development of DR found in the United Kingdom Prospective Diabetes Study,¹⁶ blood pressure can be considered during grading of teleretinal image as well.

Teleretinal screening for DR within the VAMC was reported in 2004 by the Joslin Vision Network (JVN) before its widespread national adoption in 2006.⁹ In this series of 1,219 patients, 13% of image sets were found to be ungradable as opposed to 5% in our study. This could be because our patients had less severe pathology as ungradable images have been associated with more severe pathology.¹⁷ In our population, 85% of patients did not have any evidence of DR compared to 56% of patients in the JVN study.

From the literature, referrals from teleretinal screening to eye clinic range from 20% to 30%.^18,19 In our study, more than 50% of patients were referred to eye clinic and this is, in part, because we referred all cases of DR, but other programs may only choose to refer treatment warranting cases of DR. In addition, there were high rates of nonretinal referrals such as glaucoma suspect and age-related macular degeneration. Of patients referred and subsequently examined in eye clinic, almost a third received OCT imaging. Screening with OCT in primary care clinic would improve triaging referrals to eye clinic by confirming patients with significant macular edema beforehand and scheduling them directly into a treatment clinic. Another possible reason for the high rates of referral in our study is that this particular teleretinal screening site is located on the same campus as eye clinic. The Greater Los Angeles network has seven other cameras placed in more remote locations and it is possible that other sites may not refer as readily.

One common problem among patients with diabetes and particularly Veterans is lost to follow-up. This can be due to many factors such as older age and high rates of comorbid medical conditions, mental health issues, and homelessness. In our study, lost to follow-up rates for eye care were defined as no eye clinic or teleretinal screening within 2 years of the index teleretinal screening visit and we found by these criteria a 37.5% of lost to follow-up rate. Patients who lived further from eye clinic were less likely to return to the VA for eye care after 2 years. Although it is uncertain if these patients were truly lost to follow-up or merely seeking eye care closer to their home, many patients receive their care exclusively within the VAMC. This is an important fact to investigate further in future studies.

There is a variation in how teleretinal screening occurs such as inclusion criteria and which patients are referred for further evaluation. In our center, only patients without known eye findings are screened with teleretinal imaging, which is why any level of DR is referred to eye clinic. This increases eye clinic volume and decreases teleretinal screening volume over time. Changing patient flow can be considered by limiting which patients are referred to eye clinic.

In summary, this study found rates of DR detected from teleretinal screening at the West Los Angeles VAMC to be comparable to prior studies. In addition, there was a high rate of referral to eye clinic and lack of VA follow-up, indicating that further measures for streamlining the referral system and tracking patient compliance can be targeted. Future studies comparing various VAMC screening sites should be considered.

Footnotes

Disclosure Statement

No competing financial interests exist.

References

Nathan

. Diabetes: Advances in diagnosis and treatment. JAMA, 2015; 314:1052–1062.

Klein

, Klein

, Moss

, Davis

, DeMets

. The Wisconsin epidemiologic study of diabetic retinopathy. III. Prevalence and risk of diabetic retinopathy when age at diagnosis is 30 or more years. Arch Ophthalmol, 1984; 102:527–532.

Klein

, Klein

, Moss

, Davis

, DeMets

. The Wisconsin epidemiologic study of diabetic retinopathy. IX. Four-year incidence and progression of diabetic retinopathy when age at diagnosis is less than 30 years. Arch Ophthalmol, 1989; 107:237–243.

Antonetti

, Klein

, Gardner

. Diabetic retinopathy. N Engl J Med, 2012; 366:1227–1239.

Retina Vitreous Preferred Practice Pattern. Diabetic Retinopathy. Am Acad Ophthalmol, 2016; 1–58.

American Diabetes Association. Standards of medical care in diabetes—2011. Diabetes Care, 2011; 34(Suppl. 1):S11–S61.

Jacobson

, Braffett

, Cleary

, Gubitosi-Klug

, Larkin

; DCCT/EDIC Research Group. The long-term effects of type 1 diabetes treatment and complications on health-related quality of life: A 23-year follow-up of the Diabetes Control and Complications/Epidemiology of Diabetes Interventions and Complications cohort. Diabetes Care, 2013; 36:3131–3138.

Centers for Disease Control and Prevention. Self-reported visual impairment among persons with diagnosed diabetes—United States, 1997–2010. MMWR Morb Mortal Wkly Rep, 2011; 60:1549–1553.

Cavallerano

, Cavallerano

, Katalinic

, et al. A telemedicine program for diabetic retinopathy in a Veterans Affairs Medical Center—The Joslin Vision Network Eye Health Care Model. Am J Ophthalmol, 2005; 139:597–604.

10.

Klein

, Klein

, Moss

, Davis

, DeMets

. The Wisconsin epidemiologic study of diabetic retinopathy. VI. Retinal photocoagulation. Ophthalmology, 1987; 94:747–753.

11.

Hudson

, Contreras

, Kanter

, Munz

, Fong

. Centralized reading center improves quality in a real-world setting. Ophthalmic Surg Lasers Imaging Retina, 2015; 46:624–629.

12.

Silva

, Cavallerano

, Tolson

, et al. Real-time ultrawide field image evaluation of retinopathy in a diabetes telemedicine program. Diabetes Care, 2015; 38:1643–1649.

13.

Mansberger

, Gleitsmann

, Gardiner

, et al. Comparing the effectiveness of telemedicine and traditional surveillance in providing diabetic retinopathy screening examinations: A randomized controlled trial. Telemed J E Health, 2013; 19:942–948.

14.

Tsan

, Hoban

, Jun

, Riedel

, Pedersen

, Hayes

. Assessment of diabetic teleretinal imaging program at the Portland Department of Veterans Affairs Medical Center. J Rehabil Res Dev, 2015; 52:193–200.

15.

Chasan

, Delaune

, Maa

, Lynch

. Effect of a teleretinal screening program on eye care use and resources. JAMA Ophthalmol, 2014; 132:1045–1051.

16.

Matthews

, Stratton

, Aldington

, Holman

, Kohner

; UK Prospective Diabetes Study Group. Risks of progression of retinopathy and vision loss related to tight blood pressure control in type 2 diabetes mellitus: UKPDS 69. Arch Ophthalmol, 2004; 122:1631–1640.

17.

Cavallerano

, Cavallerano

, Katalinic

, et al. Use of Joslin Vision Network digital-video nonmydriatic retinal imaging to assess diabetic retinopathy in a clinical program. Retina, 2003; 23:215–223.

18.

Owsley

, McGwin

Jr , Lee

, et al. Diabetes eye screening in urban settings serving minority populations: Detection of diabetic retinopathy and other ocular findings using telemedicine. JAMA Ophthalmol, 2015; 133:174–181.

19.

Mansberger

, Sheppler

, Barker

, et al. Long-term comparative effectiveness of telemedicine in providing diabetic retinopathy screening examinations: A randomized clinical trial. JAMA Ophthalmol, 2015; 133:518–525.