A small randomized study has found that long-term use of continuous positive airway pressure (CPAP) can slow the progression of eye disease in sleep apnea patients with non-proliferative diabetic retinopathy. However, an unexpected finding from the study showed that patients who adhered to the CPAP intervention ended up with more retinal microhemorrhages. The study, conducted at the Hospital Universitario La Paz in Madrid, Spain, and reported in Annals of the American Thoracic Society, highlights the need for closer clinical monitoring and optimal pressure settings when using CPAP for patients with diabetic retinopathy.
The trial involved 83 patients with sleep apnea and mild-to-moderate non-proliferative diabetic retinopathy. The group assigned to CPAP treatment in addition to usual care showed a significant reduction in the number of eyes with hard exudates over a year (49.1% at baseline to 29.8% at 52 weeks). In contrast, the usual-care alone group experienced no change (41.5% to 43.9%). This significant between-group difference highlights the potential benefits of CPAP in managing eye disease progression in sleep apnea patients with diabetic retinopathy.
However, the study also revealed a surprising increase in the number of retinal microhemorrhages in patients who adhered to CPAP treatment. Adequate adherence, defined as at least 4 hours per night, was associated with a 6.0 adjusted difference in the number of microhemorrhages. This suggests that the increase in retinal microhemorrhages may be directly related to the level of pressure used in CPAP treatment. The researchers speculate that repeated elevations in intraocular pressure during CPAP use may trigger mechanical irritation on the small retinal vessels, leading to wall deformations or the generation of microhemorrhages.
Diabetic retinopathy affects an estimated 9.6 million Americans, with nearly 1.8 million having vision-threatening retinopathy. The study findings suggest that it may be prudent to assess sleep apnea in patients with diabetic retinopathy, as CPAP treatment has been shown to improve hypertension and glycemic control, both of which have independent positive effects on retinopathy. Controlling sleep apnea with CPAP machines could potentially improve retinopathy by reducing oxidative stress. As Garvin Davis, MD, of Houston Methodist Hospital suggests, alongside treating hypertension and blood glucose levels, referral to sleep specialists for sleep apnea management with CPAP machines could be recommended for patients with diabetic retinopathy.
The study also found other positive effects of CPAP treatment, including improvements in sleepiness, sleep-related quality of life, and glycemic control, as well as a decrease in retinal thickness. However, these improvements did not lead to enhancements in visual acuity or intraocular pressure. The study did not observe a significant difference in serious adverse event rates between the CPAP and control groups. It is worth noting that the study had limitations, such as a higher than estimated drop-out rate and the evaluation of microhemorrhages and retinal exudates by a single ophthalmologist.
Long-term use of CPAP has shown promising results in slowing the progression of eye disease in sleep apnea patients with diabetic retinopathy. However, the unexpected finding of increased retinal microhemorrhages in patients who adhere to CPAP highlights the importance of optimal pressure settings and close clinical monitoring. Further research is necessary to fully understand the relationship between CPAP treatment and retinal microhemorrhages and to optimize its use in diabetic retinopathy management.
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