Diabetes nation: addressing an epidemic

Denver-During the American Academy of Optometry's Academy 2014, presenters shared how optometrists can help halt the diabetes epidemic and combat associated ocular complications.

"According to the CDC, of all American adults alive today, 40 percent of us will develop Type 2 diabetes within our lifetime," says A. Paul Chous, OD.

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"In the United States," says Jeffry D. Gerson, OD, "around 35 percent of diabetics have diabetic retinopathy. Around seven percent have proliferative diabetic retinopathy (PDR), and seven percent have diabetic macular edema. And 10 percent have vision-threatening diabetic retinopathy (DR). From that perspective, for every 25 exams you do, someone has DR."

Even though Type 2 risk factors such as essential hypertension, sleep deprivation, and use of drugs such as corticosteroids and lipophilic statins might not seem eye-related, Dr. Gerson added, "Most of them are things we should maybe talk to patients about. If you know someone is at risk or you see something in their eye, or if you know about their level of physical activity, it's something that we can talk to people about."

Furthermore, Dr. Gerson says, "Optometrists have a hook with patients because if you ask people what healthcare issue they fear the most, most people consistently say losing their sight. People are afraid of losing vision more than having a stroke or heart attack, or virtually anything but dying."

Among diabetes drugs, said Dr. Chous, incretins appear to preserve beta cell mass, said Dr. Chous. "Your beta cells are less likely to die off if you're on drugs like Victoza (liraglutide [rDNA origin], Novo Nordisk) or Byetta (exenatide, AstraZeneca). The problem with those drugs is that they're very expensive and require injection. But they seem to result in significant weight loss-10 to 20 pounds-in all the clinical trials. So if you tell a patient, 'I'm going to put you on a therapy that's going to lower your A1c and lower the risk of eye disease and other complications, and you're also going to lose 20 pounds, that's great. Because many diabetes medicines-especially insulin and the sulfonylureas-cause weight gain."

Ocular manifestations of diabetes

The newest drug class for Type 2 diabetes, sodium-glucose co-transport 2 (SGLT2) inhibitors, includes Invokana (canagliflozin, Janssen). Dr. Chous said, "These drugs also cause weight loss. And it's a totally new way of lowering blood sugar. When your blood sugar levels are high, most of that sugar gets reabsorbed in the kidneys. These drugs prevent the absorption of glucose by the kidneys. It spills into your urine, so you literally pee away your high blood glucose levels" while also decreasing vascular volume. Endocrinologists seem to like the newest SGL T2 inhibitor, Farxiga (dapagliflozin, AstraZeneca), more than Invokana, he added, because it causes fewer urinary tract infections. “You can also get metformin combined with Invokana (Invokamet, Janssen). SGLT2 drugs in combination with metformin work really well.”

Somewhat similarly, in a 67-patient interim analysis (NCT01646047) presented by Dr. Chous, taking a dietary supplement improved metrics including hemoglobin A1c, as well as significantly boosting patients' contrast perception, color vision, and visual field versus placebo. “The one that blew me out of my shoes was C-reactive protein, which is an established risk factor for cardiovascular disease and death. In the placebo group, it dropped around 10 percent. In the supplement group, C-reactive protein dropped 60 percent. It shows that maybe we are impacting diabetes and the early manifestations of DR through mechanisms not related to blood glucose.”