CPAP Effect on Progression of Retinal Disease in Patients with Sleep Apnea and Non-proliferative Diabetic Retinopathy: A Randomized Clinical Trial.

Obstructive sleep apnea (OSA) is associated with impaired glycemic control, and a higher risk of vascular complications, such as diabetic retinopathy. However, the effect of apnea-hypopneas suppression on retinal disease progression is unclear. To evaluate the efficacy and safety of continuous positive airway pressure (CPAP) for the reduction of retinal lesions in patients with non-proliferative diabetic retinopathy (NPDR) and OSA. This open-label, parallel-group, randomized controlled trial was conducted between October 2016 and February 2020 at a University Hospital in Spain. The date of final follow-up was March 2, 2021. 83 patients with OSA and mild-moderate NPDR receiving stable treatment were randomized to receive CPAP and usual care (43 patients, with 79 available eyes) or usual care alone (40 patients with 67 available eyes) for 52 weeks. The primary outcomes were the change in the percentage of eyes with retinal exudates and the number of retinal microhaemorrhages from baseline to week 52. We also assessed the effect of both interventions on retinal thickness by means of optical coherence tomography (OCT), serum levels of glycated haemoglobin, blood pressure, lipid levels, sleepiness, and quality of life. 52-weeks of CPAP treatment were associated with a reduction from baseline in the percentage of eyes with hard exudates (overall difference -21.7%, P=0.035) as well as in OCT indices of retinal oedema, including central subfield thickness and cube volume. However, in patients who met prespecified criteria for CPAP adherence, treatment was also associated with a higher number of retinal microhaemorrhages at 52 weeks (intergroup adjusted difference, 6.0 [95% confidence interval 0.6 to 11.5]; P=0.029), which was directly related to prescribed pressure levels. CPAP treatment also improved glycaemic control, sleepiness, and general health-related quality of life. In patients with OSA and NPDR, long-term CPAP treatment in addition to usual care may result in slower progression of retinal disease, although it could also induce an increase in retinal microhaemorrhages. The trial is registered with ClinicalTrials.gov (NCT02874313). Primary Source of Funding: Sociedad Española de Neumología y Cirugía Torácica/Spanish Society of Pneumology and Thoracic Surgery.