Undiagnosed Diabetic Retinopathy Prevalence

The leading cause of new cases of blindness in American adults aged 20-74 is diabetic neuropathy. Currently, it is estimated that the prevalence of diabetic retinopathy and sight-threatening retinopathy of US diabetic patients is 28.5% and 4.4%, respectively. With standard of care screening, timely diagnosis, and proper care, 50-70% of diabetes-related vision loss can be prevented.

Researchers from the University of Pittsburgh School of Medicine, Pittsburgh, PA sought to determine the prevalence and risk factors of undiagnosed diabetic retinopathy among diabetic inpatients and determine barriers to ophthalmic exams and treatment.

From September 2011 to August 2012, 113 inpatients (type 2 diabetes, n=108; type 1 diabetes, n=5) of an inner city community teaching hospital with a known diabetes mellitus diagnosis were enrolled in the study. Researchers administered a questionnaire and reviewed medical records to determine risk factors for diabetic retinopathy. Two ophthalmologists graded digital posterior pole fundus photographs of the patients to determine the presence, absence, and severity of retinopathy and macular edema based on internationally accepted criteria. Five patients were excluded from calculations to determine retinopathy prevalence; three were physically unable to have photos taken and two had poor quality photos. These five patients were, however, included in the barriers to care analysis.

The overall prevalence of diabetic retinopathy in this high-risk group was 44%, which is significantly higher than that of the general US population (28.5%). Renal disease (P=0.022) and longer duration of diabetes (P=0.017) were independently associated with diabetic retinopathy. Also, 88.2% of patients admitted for non-healing ulcer/osteomyelitis had diabetic retinopathy. Previously undiagnosed diabetic retinopathy and sight-threatening retinopathy was 25% and 19%, respectively.

Of interest, the authors noted that 91% of study participants were aware of the ocular complications of diabetes. Additional studies mentioned in the article list patients’ lack of awareness due to lack of education or instruction as the reason the general diabetic population does not have annual dilated eye exams.

While the inpatient population was aware of the risk of diabetic neuropathy and 64% had ophthalmologists, only 40% followed recommended standard screening exams. Common barriers of care were transportation/physical disability, too sick/too many other medical appointments, affordability, and lack of time.

Several limitations of the study were noted, including the restricted study population and lower overall socioeconomic demographic, limitations of posterior pole fundus photos for screening diabetic retinopathy, and exclusion of patients too sick to be screened.

The authors note, “…a significant percentage of these patients are likely to have undiagnosed

or sight-threatening disease despite being under medical care. These patients have unique barriers that need to be addressed in order to make standard of care ophthalmic examination and treatment possible.”

Take-home Points

• Diabetic retinopathy prevalence was significantly higher in an inpatient versus an outpatient setting.

• One-quarter of the inpatients studied had undiagnosed retinopathy.

• Hospital admittance for a non-healing ulcer, longer duration of diabetes, and history of renal disease were associated with a diagnosis of retinopathy.

Reference: Kovarik JJ, et al. Prevalence of undiagnosed diabetic retinopathy among inpatients with diabetes: the diabetic retinopathy inpatient study (DRIPS). BMJ Open Diabetes Res Care. 2016 Feb 16;4(1):e000164.