The prevalence of diabetic retinal disease increased between 2016 and 2021 among patients with type 1 diabetes and type 2 diabetes, while incidence of overall disease declined in type 1 diabetes and moved closer to rates seen in type 2 diabetes by 2022, according to a recent study.
Researchers analyzed administrative claims data from Optum’s Clinformatics Data Mart database, which includes commercial insurance and Medicare Advantage plans across the US. The study included 3,682,484 patients with diabetes, including 101,579 with type 1 diabetes and 3,580,905 with type 2 diabetes.
The primary outcome was yearly prevalence and incidence of diabetic retinal disease (DRD). Secondary outcomes included vision-threatening diabetic retinal disease (VTDR), defined as diabetic macular edema (DME) or proliferative diabetic retinopathy (PDR), as well as DME and PDR individually.
Rising prevalence across both groups
DRD prevalence increased steadily in both groups. Among patients with type 1 diabetes, prevalence rose from 25% in 2016 to 34% in 2021. Among patients with type 2 diabetes, prevalence increased from 11% to 21% over the same period.
Patients with type 1 diabetes had higher prevalence of DRD than those with type 2 diabetes in every year studied, although the relative difference narrowed over time.
A similar pattern was observed for more severe disease:
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VTDR prevalence increased from 12% to 17% in type 1 diabetes and from 4% to 6% in type 2 diabetes
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DME prevalence rose from 5% to 8% in type 1 diabetes and from 2% to 4% in type 2 diabetes
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PDR prevalence increased from 9% to 13% in type 1 diabetes and from 2% to 3% in type 2 diabetes
Diverging patterns in incidence
Incidence findings showed a more complex pattern.
Overall DRD incidence in type 1 diabetes declined from 55.1 cases per 1,000 person-years in 2016 to 39.2 in 2022. In type 2 diabetes, incidence ranged from 31.6 to 38.5 cases per 1,000 person-years during the study period and was 35.5 in 2022.
This shift reduced the relative difference between groups. The incidence rate ratio for type 1 vs type 2 diabetes declined from 2.00 in 2016 to 1.43 in 2022, indicating that overall DRD incidence in type 1 diabetes moved closer to that of type 2 diabetes by the end of follow-up.
However, this convergence was not seen across all disease subtypes. VTDR, DME, and PDR incidence remained consistently higher in type 1 diabetes throughout the study period, with relative differences remaining largely stable overall. For PDR, the disparity widened over time.
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VTDR incidence decreased from 23.3 to 14.5 cases per 1,000 person-years in type 1 diabetes and from 11.0 to 6.6 in type 2 diabetes
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DME incidence declined from 17.8 to 10.0 in type 1 diabetes and from 8.7 to 5.4 in type 2 diabetes
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PDR incidence decreased from 12.1 to 9.3 in type 1 diabetes and from 4.6 to 2.7 in type 2 diabetes
Persistent disparity despite improvement
“The incidence of T1DM DRD decreased, approaching the rate of T2DM in 2022,” wrote lead researcher Sonny Caplash of the University of Pennsylvania, and colleagues. They also noted that “all forms of DRD had uniformly higher prevalence and incidence in patients with T1DM compared with those with T2DM across all years observed.”
The researchers suggested that increasing prevalence may reflect the growing population of patients with diabetes as well as longer survival among those living with complications. At the same time, advances in diabetes care may be contributing to declining incidence, particularly in type 1 diabetes.
Limitations
The study relied on administrative claims and diagnostic coding rather than chart-level validation, although prior studies have validated the ICD codes used for diabetic retinal disease, diabetic macular edema, and proliferative diabetic retinopathy.
The data set was not nationally representative and did not include uninsured patients or those covered by certain health systems. In addition, the analysis lacked clinical details such as diabetes duration and glycemic control. Changes in health care utilization during the COVID-19 pandemic may also have influenced results in 2020 and 2021.
Conclusion
Overall, patients with type 1 diabetes continued to have a higher burden of diabetic retinal disease than those with type 2 diabetes, even as the incidence gap for overall disease narrowed over time.
Disclosures The researchers reported no known competing financial interests or personal relationships that could have influenced the work.