Diabetic Retinopathy: 2-Year Screening Interval May Be Okay

Miriam E. Tucker

February 08, 2019

People with diabetes who have minimal or no retinopathy at initial screening are unlikely to progress to the point of requiring retinopathy treatment within 2 years, but the question of optimal screening intervals is still open, new research and commentary suggest. 

Results from a retrospective analysis of data from the large Kaiser Permanente Southern California Eye Monitoring Center population were published online February 7 in JAMA Ophthalmology by researchers from the center, led by Bobeck S. Modjtahedi, MD.

Among nearly 80,000 patients with diabetes who had minimal or no diabetic retinopathy at baseline screening, fewer than 25 individuals required any diabetic retinopathy-related treatment over 2 years.

The American Academy of Ophthalmology recommends a minimum of yearly screening examinations, with shorter intervals for patients with increasing diabetic retinopathy severity. The American Diabetes Association says that 2-year intervals "may be considered" for those with no retinopathy at baseline, but advises annual exams for any degree of baseline retinopathy.

"The findings suggest that extending follow-up examinations for patients with minimal or no baseline diabetic retinopathy may be warranted because most may not need retinal intervention within 2 years of initial evaluation, provided this extension does not lead to worse follow-up in later years," Modjtahedi and colleagues write.

But the possibility of losing patients to future follow-up is one of several issues raised by Peter van Wijngaarden, PhD, Centre for Eye Research Australia, East Melbourne, and colleagues in an accompanying editorial.

"There is likely to be a tipping point at which compliance with screening falls off as screening intervals extend because longer intervals may minimize perceived risk and thus patient engagement," Wijngaarden and colleagues write.

The broader healthcare context is key, the editorialists note. "If a diabetic retinopathy screening program is embedded in the health system, longer intervals are less likely to result in loss of participation. Experience in health systems where screening is ad hoc, such as in Australia, suggests that compliance with biennial screening is suboptimal."

Overall, Wijngaarden and colleagues say that the new study is "noteworthy because it adds to a growing body of evidence that suggests that extending screening intervals to 2 years for those with no or minimal diabetic retinopathy at baseline may be safe and appropriate," but nonetheless "in isolation, it does not provide sufficient evidence to support the case for biennial screening."

Without Retinopathy at Baseline, Few Need Treatment Within 2 Years

The study population included 69,634 patients without retinopathy and 9811 with minimal retinopathy at baseline screening, all of whom had 2-year follow-up data available.

Among those with no baseline retinopathy, just 11 required initiation of retinopathy-related treatment within the subsequent 2 years, and 44 required retinal interventions not directly related to diabetic eye disease. These translate to rates of 0.000079 patients (or 1 of 12,660) per year requiring intervention for diabetic retinopathy and 0.000316 patients (1 of 3165) per year requiring interventions for nondiabetic eye conditions.

In the group with minimal retinopathy at baseline, treatment for diabetic retinopathy was also initiated in just 11 (1 of 1784, or 0.000561 patients per year), while five patients required retinal interventions unrelated to diabetes (1 of 3924 or 0.000255 patients per year) over the 2-year follow-up.

The most common procedures were panretinal photocoagulation of proliferative retinopathy for diabetic retinopathy and pars plana vitrectomy for nondiabetes-related eye disease.  

Editorialists Express Caution About the Study

The editorialists caution that the study is retrospective, doesn't capture care delivered outside the health network, and that 15% of patients were lost to follow-up. Moreover, they note, the severity of retinopathy at 2 years wasn't reported, nor is baseline “minimal” retinopathy clearly defined.

Wijngaarden and colleagues add that the generalizability isn't clear because baseline characteristics of patients, such as diabetes duration, HbA1c, blood pressure, and comorbid diabetes complications, aren't provided in the article, which was published as a brief research report.

Modjtahedi and colleagues also advise caution about their own findings. "Efforts to extend follow-up intervals would need to ensure that adherence at later years is not compromised. Most interventions were rendered for conditions not directly related to diabetic retinopathy. Additional study is required to determine the ideal screening intervals for patients with diabetes."

Modjtahedi has reported no financial relationships. Two coauthors have received grants from Allergan, one of whom also received grants from Regeneron, ThromboGenics, and Nightstar. Wijngaarden and colleagues have disclosed no relevant financial relationships.  

JAMA Ophthalmology. Published online February 7, 2019. Abstract, Editorial

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