Between 3/14/2016 and 5/26/2017, 689 digital retinal screening exams (1,377 fundus photographs) were conducted in Temple’s primary care clinic. Six hundred sixty-three patients received one screening, while 26 patients received two screenings during this span of time. Of the 689 encounters, 404 (58.6%) women and the median age at the time of encounter was 59 years (range, 18 – 94 years). Five hundred forty-four (79.0%) screenings were performed on African Americans and 75 (10.9%) on Hispanics. The remaining 70 screenings (10.2%) were attended by Caucasians, unspecified or mixed race patients, Asian/Pacific Islanders, and Native Americans. At the time of screening, 277 (40.2%) of 689 patients had a form of Medicare, 238 (34.5%) had a form of Medicaid, 152 (22.1%) had private insurance, and 20 patients (2.9%) had no insurance (Table 1). For comparison, Temple University Hospital’s North Philadelphia community has 464,455 residents, of which, 46% are African American, 30% are Hispanic and 18% are White. Fifty-three percent of this population is 50 or older, and 46% are covered by Medicaid with 40% covered by Medicare.11
Figure 2 depicts the breakdown of fundus photograph quality in each eye. For the right eye, 356 (51.7%) of 689 photographs were specified as good quality, while 114 (16.5%) fair, 208 (30.2%) poor, and 11 (1.6%) unspecified either due to ocular condition or for unknown reason. A similar distribution of quality was noted for photographs of the left eye in which 336 (48.8%) of 688 photographs were specified as good, 112 (16.3%) were fair, 232 (33.7%) were poor, 8 images (1.2%) were unspecified, and 1 image was unavailable. The mean and median length of time between the screening visit and the fundus photo interpretation was 55.4 and 23 days, respectively (range, 0 – 418 days).
We photographed 1377 eyes of 689 patients. Among them, 928 (67.4%) photos were gradable and 449 (32.6%) were unable to be assessed. Figure 3 displays the DR assessment of each fundus photograph that was able to be graded. Of these 928 graded images, 755 (81.4%) were read to have no retinopathy, 56 (6.0%) were read as DR with no modifier, 78 (8.4%) mild, 16 (1.7%) moderate, 19 (2.0%) severe, and 4 (0.4%) were graded as PDR.
When analyzing data in terms of patients, 343 (49.8%) of 689 patients were found to definitively have no DR in either eye based on fundus photography. 103 patients (14.9%) were found to have some level of DR in at least one eye (70 (10.2%). Of the 103 patients with at least some DR in at least one eye, 33 (4.8%) patients had at least one image graded as ‘unspecified DR’. Of the 70 patients with specified grades of DR, 48 (68.6%) had mild, 9 (12.9%) had moderate, 11 (15.7%) had severe, and 2 (2.9%) had proliferative DR in one or both eyes.
Of the remaining 243 patients, as 193 (28.0% of 689 total) of them were unable to be assessed in both eyes and 50 (7.3% of 689 total) of them lacked DR in one eye but were unable to be assessed in the other (Figure 4).
Sixty-seven (9.7%) of 689 patients were suspected to have another ophthalmic condition based on other findings in the retinal photographs. The most frequently encountered findings were those associated with glaucoma, hypertensive retinopathy such as vascular tortuosity, and macular or peripheral drusen.
Among the 689 screening exams, 357 (51.8%) resulted in a request for a referral to ophthalmology. Referrals were requested for DR found in one or both eyes, inability to assess presence of retinopathy in one or both eyes, or for suspicion of a different ophthalmic diagnosis. One hundred ninety-six (54.9%) of the 357 referrals resulted from an inability to assess DR in at least one eye, 101 (28.3%) were for some level of DR detected in at least one eye, 38 (10.6%) were for suspicion of another ophthalmic condition, Nine (2.5%) had at least one photograph that was unable to be assessed as well as suspicion for another condition, and 13 (3.6%) were referred in error since they had no suspicion of DR or another condition (Figure 5). Of note, there were two instances of patients with detected DR or another ocular condition that did not result in a referral request.
We counted specialist appointments as being the result of the screening if the appointments were scheduled within a timeframe of 190 days from the digital fundus image interpretation date. Sixty (16.8%) of the 357 referral requests resulted in a scheduled appointment with the ophthalmology clinic. Two hundred ninety-six (82.9%) of the 357 referral requests did not result in an appointment being made. Among the 60 appointments, only 33 (55.0%) patients showed to the appointment while the other 27 (45.0%) appointments were either no-showed or cancelled (Figure 6). The mean and median number of days between fundus photograph interpretation and scheduled ophthalmology appointment was 70.6 and 60.0 days, respectively (range 0-190 days).
Among the 33 patients that were successfully referred to Temple ophthalmology, there was good concordance between the level of DR detected by their screening fundus photographs and that diagnosed by specialist-performed dilated fundus exam (DFE). Eleven (32.4%) of the 33 patients were referred due to detected DR in at least one eye by the screening. Nine (82%) of these 11 were confirmed to have DR by on exam. Twenty-two (66.7%) of these 33 patients were referred, either due to inability to assess the photos or lack of findings. On exam, 17 (77.2%) of these 22 were confirmed to not have DR, while an assessment was unable to be made for one patient due to their visit focusing on their glaucoma as an undilated exam. Of the other five patients, one was found to have severe DR, two were found to have PDR, and two were diagnosed with unspecified DR. Among those patients in which a graded assessment was made by both the screening exam and the DFE, only one had significantly discordant findings – in this patient, the screening assessed mild retinopathy in both eyes and the DFE diagnosed PDR..
We recorded the HgbA1c for 674 (97.8%) of 689 patients who had a documented value within 6 months of their respective screening dates. The average HgbA1c among these was 8.05% (range, 4.2 – 18.1%). Though not statistically significant, the 26 patients who had two screenings during our study period had an average A1c of 8.56% at the first visit and an average of 7.48% at the second, for an average reduction of 1.08% between visits (p=0.054). At the time of screening, 116 of 689 (16.8%) patients were diet-controlled, 309 (44.8%) patients were being managed with only oral medication, and 264 (38.3%) were insulin-dependent (Table 1). More intensive diabetic therapy and higher A1c correlated with that of some degree of retinopathy in this patient cohort, demonstrated in figures 7 and 8, respectively. For those patients with gradable fundus photographs, 7/155 (4.5%) of the photos from diet-controlled diabetics displayed at least some level of DR compared to 57/444 (12.8%) and 108/328 (32.9%) of the photos of diabetics controlled with oral medications and insulin, respectively (p<0.0001). Moreover, 53/560 (9.5%) of the images from patients with an HgbA1c between 4.0 and 7.9 showed DR as compared to 99/289 (34.3%) and 18/58 (31.0%) of those groups with values between 8.0-11.9 and >12.0, respectively (p<0.0001). The prevalence of diabetic retinopathy between the 8.0-11.9 and >12.0 A1c groups was not statistically significant (p=0.75) and was actually found to be higher in the lower A1c group (34.3% as opposed to 31.0%).
Overall Demographics
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Number of Encounters
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689.0
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Male/Female
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285/404 (58.6% female)
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Mean age at screening (years)
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59.3
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Average HbA1c
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8.1
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Ethnicity
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African American
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544 (79.0)
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Hispanic
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75 (10.9)
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Caucasian
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26 (3.8)
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Asian/Pacific Islander
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5 (0.7)
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Indian
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1 (0.1)
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Other or Mixed
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38 (5.5)
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Insurance
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|
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Medicare
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277 (40.2)
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Medicaid
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238 (34.5)
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Private
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152 (22.1)
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None
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20 (2.9)
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Medication Use
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|
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Diet Only
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116 (16.8)
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Oral Medication Only
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309 (44.8)
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Insulin Dependent
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264 (38.3)
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|
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*Data is reported as number (%).
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Table 1. Patient Demographics.