In the 5 decades that physicians have been treating diabetic retinal diseases (DRDs), their knowledge about these disorders has substantially increased. However, the staging system used to help define and direct diagnosis and treatment hasn’t evolved along with that growing body of knowledge, according to an editorial published in Ophthalmology. The physician authors are advocating for a new staging system to better serve patients with diabetic eye diseases.
Disease staging systems are vital for framing clinical care and research. To be effective, they must be easy to understand, correlate with clinically significant endpoints, and reflect disease pathophysiology, among other things. The Early Treatment Diabetic Retinopathy Study (ETDRS) scale has served as the predominant staging system for diabetic retinopathy (DR). However, according to the article’s authors, both ETDRS and the international DR grading scale have limitations, including that neither is quantitative or linear and both only evaluate the vascular component of DR existing within the 7 standard photographic fields. They don’t incorporate the pathophysiologic or neurodegenerative changes that occur before clinically evident retinopathy develops. Further, neither scale is well suited for documenting progression or regression of neovascularization in eyes with proliferative DR. Regarding ETDRS specifically, the scale’s scoring wasn’t designed to assess the efficacy of interventions that improve DR severity, specifically regarding visual function. Lastly, neither scale adequately defines severity stages for diabetic macular edema.
Progress in the field supports the need for an updated staging system to incorporate relevant advances and provide prognostic information necessary to better address early disease, disease progression, development, use of therapeutic interventions, and treatment effectiveness, according to the piece’s authors, a group that includes Jennifer K. Sun, MD, MPH, of the Beetham Eye Institute and Joslin Diabetes Center in Boston.
“We propose it is an appropriate time to start developing a revised, multidimensional DRD severity scale that can be used to better define DRD, stage individual risk for disease worsening, predict and measure response to therapy, and support clinical trials evaluating novel therapies while having a readily usable interface for both researchers and clinicians,” the article explains. “The road toward developing, testing, and implementing an updated staging system for DRD will necessitate involvement of multiple stakeholders, including scientists, clinicians, regulatory agencies, and patients.”
Validation will be an essential step in developing a new system and should be based on carefully defined and clinically relevant outcomes performed using “rigorous and statistically valid” methodologies, according to the authors. Any revised system must address the risk of visual loss, but also could include quality of life/autonomy outcomes or predict prognosis and response to therapy, they say. As such, more than one severity scale with different levels of granularity may be necessary. The group’s proposed schematic for a new scale is designed to address retinal, neural, and vascular pathology and their contributions to visual function in the context of systemic influences like diabetes type, glycemic control, blood pressure, renal disease, and anemia.
Regulatory acceptance of a revised staging system also will be key, according to the authors.
Sun JK, Aiello LP, Abràmoff MD, et al. Updating the staging system for diabetic retinal disease. Ophthalmol. Published online November 17, 2020. doi: 10.1016/j.ophtha.2020.10.008