Diabetic patients who take statins to treat high cholesterol may get an added benefit: a lower risk of damage to the retina, a new study suggests.
Researchers found that diabetic patients taking statins were 14 percent less likely to develop retinopathy than those who were not. And among patients who did develop retinopathy, statin therapy was associated with slower disease progression, according to Dr. Eugene Yu-Chuan Kang, a researcher at Chang Gung Memorial Hospital in Taiwan, and colleagues.
Diabetes leads to retinopathy through damage to the blood vessels in the eyes, said Dr. Szilard Kiss, director of the retina service and director of tele-ophthalmology at NewYork-Presbyterian/Weill Cornell Medical Center in New York City.
Ultimately, people can go blind from diabetic retinopathy.
“The retina is like the film in a camera,” explained Kiss, who was not involved in the new study. “Diabetes causes the blood vessels to become leaky, which causes swelling in the retina.”
When the blood vessels leak, they spill a host of substances in the blood, including cholesterol into the retina, Kiss said. As of yet, scientists aren’t sure exactly how cholesterol might be causing eye damage.
As reported in JAMA Ophthalmology, the research team pored through the Taiwanese National Health Insurance Database, ultimately finding 740,326 patients who had received a diagnosis of type 2 diabetes between 1998 and 2013 and who also had high cholesterol. The researchers winnowed that number down to 219,359 patients, 199,760 of whom were taking statins and 19,599 who were not.
The researchers ultimately settled on a comparison of 18,947 patients on statins and 18,947 who were not taking the cholesterol lowering medications. After an average follow-up of seven years, retinopathy had developed in 2,004 patients taking statins, or 10.6 percent, compared to 2,269, or 12 percent, of those who did not take the medications.
Along with a lower rate of diabetic retinopathy, statin use was also linked with a lower need for invasive treatments for the eye disease, the researchers reported.
Clinical trials have shown that cholesterol-lowering drugs can impact the risk of diabetic retinopathy, Kiss said. “But this is a very valuable type of study,” he added. “It’s another level of evidence and confirms in the real world that treating dyslipidemia can have an effect on diabetic retinopathy.”
“The study reiterates the importance of treating hyperlipidemia in the presence of diabetes,” Kiss said. “We focus so much on blood sugar in these patients, which is important of course, but we shouldn’t forget about the lipids.”
It’s important to remember that this is just an observational study, said Dr. Seth Martin, a professor of medicine and director of the advanced lipid disorders program at the Ciccarone Center for the Prevention of Heart Disease at Johns Hopkins Medicine. As such, the findings show an association but don’t prove that statins led to lower rates of retinopathy.
“But it’s a really interesting study that was done in a large number of patients,” Martin said. Moreover, “it’s reassuring that there was decreased retinopathy in those taking statins.”
In the end, Martin said, the main reason to be taking statins is to lower the risk of heart disease. The potential impact on the eyes of diabetic patients could be an added benefit.
“There’s been a large increase in diabetes over time,” Martin said. “It’s a really important condition that carries cardiovascular risk that people often don’t recognize or realize how large of a risk it is.”