Research presented at last month’s Annual Meeting of the American Academy of Ophthalmology suggests that severe sleep apnea is a risk factor for developing diabetic macular edema (DME), a complication of diabetes that can cause vision loss or blindness. The small study was done in Taiwan under the direction of Juifan Chiang, M.D., who expressed his hope that “more professionals will approach sleep apnea as a risk factor for DME,” allowing for earlier intervention. Whether health insurance companies will respond by considering earlier treatment recommendations for diabetics with severe sleep apnea to be medically necessary remains to be seen. What now seems more clear in the wake of this study is that sleep apnea exacerbates underlying eye disease. Moreover, earlier medical intervention will be important for diabetics with severe sleep apnea as the research shows that these patients needed more treatment to control their DME.
Dr. Chiang and his colleagues examined data from 51 patients diagnosed with diabetic retinopathy over an eight-year period at Chang Gung Hospital in Taiwan. 97 eyes were studied. The researchers hypothesized that obstructive sleep apnea (OSA), a sleep disorder in which breathing intermittently stops and starts, could potentially contribute to the development and worsening of diabetic retinopathy. Because OSA causes blood oxygen levels to drop, a variety of changes in the human body take place, including increases in insulin resistance, inflammation, and blood pressure. All of these changes can damage the blood vessels at the back of the eye, which causes diabetic retinopathy. Patients with diabetic retinopathy are at risk for DME.
The study found that the rate of severe OSA was significantly higher in patients with DME compared to those without. The rate was nearly double (80.6% vs. 45.5%). They also found that the worse the sleep apnea was, the worse the DME. Severe sleep apnea was also more prevalent in patients who needed more treatment (three or more treatments of medical or laser therapy) to control their DME.
It should be noted that the retrospective analysis had limited information about treatment and compliance with continuous positive airway pressure (CPAP), the treatment of choice for OSA. Commentators have said that a larger prospective study is needed to examine whether CPAP affects the relationship between OSA and DME.
Because the study found that DME is more difficult to treat in patients with severe sleep apnea, earlier intervention is important, and should, as Dr. Chiang hopes, allow patients to “keep more of their vision and preserve their overall health as much as possible.” Diabetics diagnosed with sleep apnea should be followed closely by an ophthalmologist. Weight loss, as well as avoiding alcohol and smoking, should be encouraged, as doing so can reduce and even cure sleep apnea. Early treatment of diabetic retinopathy in patients with sleep apnea should include maintaining good blood sugar, blood pressure, and cholesterol control, and keeping a healthy lifestyle. As the results of the study are circulated, it will be interesting to see whether earlier surgical intervention or anti-VEGF medication will be considered for diabetics with severe sleep apnea - and whether insurance companies will deem such treatment medically necessary. Stay tuned.
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