By Marilynn Larkin
NEW YORK (Reuters Health) - 1/2/2019
Strong glycemic control may optimize vision outcomes in patients with diabetic macular edema (DME) treated with anti-vascular endothelial growth factor (anti-VEGF) therapy, researchers say.
Dr. Jennifer Sun, chair of Diabetes Initiatives for the Diabetic Retinopathy Clinical Research (DRCR) Network, and colleagues conducted a post hoc analysis of the network’s multicenter randomized clinical trial Protocol T, which compared three commonly used anti-VEGF agents in patients with central-involved DME and vision impairment (20/32 or worse).
Participants (median age, 61) received repeated 0.05-mL intravitreous injections of 2.0-mg aflibercept, 1.25-mg bevacizumab, or 0.3-mg ranibizumab in one eye.
For the current study, Dr. Sun and colleagues analyzed data on 578 participants. Outcomes were change in visual acuity (VA) and optical coherence tomography (OCT) central subfield thickness at two years, and change in VA over two years (area under the curve; AUC).
As reported online January 24 in JAMA Ophthalmology, across anti-VEGF treatment groups, each baseline factor was associated with a mean improvement in VA and a reduction in central DME compared with baseline.
For example, for every decade of participant age, the mean VA improvement was reduced by 2.1 letters in the VA analysis and 1.9 letters in the VA AUC analyses.
For each 1% increase in hemoglobin A1c levels, VA improvement was reduced by one letter in the VA and 0.5 letters in the VA AUC analyses.
Eyes with no prior panretinal photocoagulation (PRP) and less than severe nonproliferative diabetic retinopathy had an approximately three-letter improvement in the VA and VA AUC analyses compared with eyes with previous PRP.
Further, on average, African American participants had greater reductions in central subfield thickness compared with eyes of white participants (−27.3 micrometers), as did eyes with central subretinal fluid compared with eyes without this OCT feature (−22.9 micrometers).
In the final multivariable analysis, younger age, lower HbA1c levels, and the absence of previous panretinal photocoagulation were associated with larger gains in VA.
No significant differences were seen among anti-VEGF agents for any VA or OCT outcome.
“Given the post hoc nature of the analyses, these results should be viewed as hypothesis-generating rather than definitively influencing practice,” Dr. Sun said in an email to Reuters Health. “However, these findings provide useful evidence to help motivate physicians and patients to maintain strict glycemic control.”
“I discuss these findings with my patients to encourage them to work closely with the physician managing their diabetes and to follow their physician’s recommendations regarding their glycemic targets,” she noted.
Dr. Sobha Sivaprasad of University College London Institute of Ophthalmology in the UK, author of a related editorial, told Reuters Health the findings reassure clinicians “that outcomes are predicted to be similar regardless of type of VEGF treatment.”
“Another important observation that should guide our clinical practice is that we need to unreservedly continue to advise our patients to aim for optimal control of diabetes,” she said by email.
“It is worth informing patients already treated with PRP for proliferative diabetic retinopathy that our aim in treating the diabetic macular edema with anti-VEGF is geared at stabilization of VA rather than significant improvement in VA,” she concluded.