Vision-Threatening Forms of Diabetic Retinal Disease Have Plummeted

DENVER — Prevalence of diabetic retinal disease (DRD) declined modestly over a 20-year period, while severe forms dropped substantially, a large retrospective cohort study showed.

Overall, the hazard ratio for progression to DRD decreased 20% from 2002 to 2022, but most of the decline occurred during the first 10 years. Thereafter, more at-risk patients with diabetes progressed to DRD.

However, progression to more severe, vision-threatening forms of DRD showed a different epidemiologic picture, as the hazard for vision-threatening diabetic retinopathy (VTDR) decreased by 55%, diabetic macular edema (DME) by 47%, and proliferative diabetic retinopathy (PDR) by 70% over the study period.

The seemingly conflicting findings reflect changes in diabetes treatment and screening for DRD, as well as limitations inherent to retrospective analyses, said Brian VanderBeek, MD, MPH, of Scheie Eye Institute Penn Presbyterian in Philadelphia, at the Association for Research in Vision and Ophthalmology meeting.

“Patients with diabetes are 20% less likely to progress to any form of diabetic retinopathy compared to 2002 but still not quite as good as the 35% decrease we saw from 2010 to 2012,” said VanderBeek. “We have seen a dramatic reduction in progression to vision-threatening disease and its components, including any vision-threatening disease, diabetic macular edema, and proliferative retinopathy.”

Summarizing the study from a good news/bad news perspective, he added, “Unfortunately, we’re at 20-year highs for prevalence and incidence. However, there is good news underlying that data,” said VanderBeek. “We are dramatically better at preventing vision-threatening disease, which is the most important part. Many of the new medications do seem to be better at preventing diabetic retinal disease as a whole, even though we have a big, scary number [of patients] joining us. We have to keep our eye on the ball, because we have this huge population that has diabetic retinal disease. We can’t let up. We have to make sure that we care for patients.”

During a discussion that followed the presentation, co-moderator Yih Chung Tham, PhD, of the National University of Singapore, asked about the potential influence of artificial intelligence (AI)-based DRD screening on the results.

“I don’t know how much AI screening was done during this study. That’s been more recent,” said VanderBeek. “I know there are some screening programs that might have been going on at the time. In general, screening has increased. It’s been a big emphasis in the U.S., and I’m sure elsewhere, to try and get people though the door and get them checked for eye disease. Historically, we haven’t been great, but we are doing much better.”

An unidentified member of the audience alluded to the recent subtyping of diabetes by specific characteristics and asked whether changes in the contributions of different subtypes might have influenced the results. Specifically, he asked whether more cases might have shifted from obesity-related diabetes to “mild” age-related diabetes.

“I don’t know that we have that data,” said VanderBeek. “I can say that in the data we do have, 97% of the disease is type 2, so type 1 is not a big factor.”

The study had its origin in the lack of information about the cumulative impact of recent therapeutic developments in diabetes on the risk of progression to DRD, particularly VTDR. In an effort to inform the issue, VanderBeek and colleagues performed a retrospective cohort study using data from private medical insurers and Medicare Advantage plans.

The analysis included patients with newly diagnosed diabetes during 2003-2022. All patients had at least 2 years of follow-up, and the primary outcomes were the yearly rate of progression to DRD and progression to VTDR, including DME and PDR.

Data analysis included 4.2 million patients with diabetes who were at risk for progression to DRD. Over the 20-year study period, 143,000 patients progressed to DRD, 46,000 had progression to VTDR, 28,000 progressed to DME, and 20,000 progressed to PDR.

The 2-year cumulative incidence of progression to DRD was 6% in 2003 and had declined to 5% in 2022. Some degree of improvement occurred almost every year after 2002, said VanderBeek. The decrease from baseline reached a maximum of about 35% from 2010 to 2013, then showed a reversal thereafter until the 20-year difference in the hazard ratio was just 20%.

For the more severe forms of DRD, little change in the hazard ratios was observed during the first 5 to 6 years, then they declined almost every year after 2008.

Lack of information on disease duration is a key limitation of the analysis. Investigators were able to adjust for comorbidities, using the Diabetes Complications Severity Index (DCSI), which made a difference in the results. An unadjusted analysis showed little improvement in progression to DRD over time. After adjustment for comorbidities, “it looks like we’re doing much better than we could have been had we not had some of the advancements,” said VanderBeek.

“Someone who has had [diabetes] for 10 years and has multiple complications but doesn’t have eye disease is much more likely to progress to eye disease than someone who has had diabetes for 20 years and doesn’t have any complications. [The DCSI] has actually been shown to be a better predictor of hospitalization and death, and it’s highly correlated with DRD progression.”

The age at onset of DRD might also have influenced the findings. VanderBeek and colleagues have found that patients older than 65 account for a growing percentage of DRD, “which is consistent with pushing back the start of diabetic retinal disease. Other aspects of age are impacting their health. They’re passing away before they get to vision-threatening disease, so we’re not seeing as much vision-threatening disease as we’ve seen before.”

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