Algorithmic formulations may help manage diabetic macular edema

October 15, 2005

By its nature, diabetic macular edema (DME) is somewhat resistant to simple algorithmic formulations because of the multifactorial nature of the decision-making process and the host of new therapies that continually become available, explained Julia Haller, MD, during retina subspecialty day at the American Academy of Ophthalmology annual meeting.

Chicago-By its nature, diabetic macular edema (DME) is somewhat resistant to simple algorithmic formulations because of the multifactorial nature of the decision-making process and the host of new therapies that continually become available, explained Julia Haller, MD, during retina subspecialty day at the American Academy of Ophthalmology annual meeting.

“Despite this, it is possible to devise a relatively simple checklist to manage DME,” she stated. Dr. Haller is the Katharine Graham professor of ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.

She proposed that excellent metabolic control is the first step in managing these patients. This includes control of glycemia and hypertension as well as lipid control. In some patients, metabolic control alone can bring the serum values into the normal range and improve the condition of the fundus.

The second step is construction of a long-term plan with the patient based on complete ocular evaluation. Whether the patient is phakic or aphakic should be determined because cataract planning may be important when DME is being treated. The status of the optic nerve may determine whether or not steroids are prescribed. The degree of retinopathy is also important, Dr. Haller emphasized.

Step three involves ruling out other treatable causes of macular edema using diagnostic tests such as fluorescein angiography and optical coherence tomography.

Step four is the gold standard, that is, treatment with laser photocoagulation, which can reduce vision loss by more than 50%.

Step five is careful follow-up and assessment of the treatment response. Despite laser treatment, many eyes have progressive visual loss.

Step six involves re-treatment or consideration of other options such as off-label use of available drugs such as triamcinolone acetonide, pegaptanib sodium (Macugen, OSI/Eyetech Pharmaceuticals), bevacizumab (Genentech), or the Retisert (Bausch & Lomb) implant.

Clinical trial enrollment is another possibility and these include the Diabetic Retinopathy Clinical Research Network, the Posurdex trial (Allergan), the ranibizumab (Genentech) trial for DME, and the pegaptanib sodium trial for DME. Another option is combination treatment that includes an established treatment with some new pharmacotherapies. This is a very exciting new avenue, Dr. Haller explained.

“I think it is possible to construct a management algorithm for DME that rests on a basis of superb metabolic control, complete ocular evaluation, careful consideration of confounding factors, the gold standard of ETDRS laser treatment, and judicious use of new therapies as they emerge,” she said.

“Finally, I urge all physicians to consider referring appropriate patients for enrollment in studies,” Dr. Haller said. “By carefully sorting through the potential therapies and combinations of therapies we will be able to construct intelligent algorithms to advise our patients with diabetes responsibly.”