Evaluation of posterior ocular changes using enhanced depth imaging-optical coherence tomography in patients with obstructive sleep apnea syndrome.

PURPOSE: Evaluation of the nerve fiber thicknesses of the macula, choroid, and retina using the apnea-hypopnea index in individuals with obstructive sleep apnea syndrome (OSAS) without systemic components. METHODS: Prospective, controlled study. The central macular, choroidal, and retinal nerve fiber layer (RNFL) thicknesses were evaluated using enhanced depth imaging-spectral domain optical coherence tomography in individuals with OSAS. In people with severe OSAS who had received treatment, posterior ocular structures were examined over 3 months (4th and 12th weeks), and changes were evaluated. Only the right eyes of the participants were evaluated in the study. RESULTS: A total of 72 people were involved in the study, with 18 in the control group and 19 with mild, 16 with moderate, and 19 with severe OSAS. No significant difference was found among the groups in terms of demographic measures. No significant differences were found among the groups in terms of the measures of central macular, central subfoveal choroidal (CSCT), temporal choroidal, nasal choroidal, and RNFL thicknesses. In severe OSAS cases in which treatment was administered, although subjective clinical recovery was observed, statistically significant thinning was detected during the 3-month follow-up period in the CSCT, general RNFL, as well as in the inferior and superior nasal quadrants, and temporal superior quadrant (p=0.005, p=0.009, p=0.039, p=0.003, and p=0.02, respectively). CONCLUSION: In the group with severe OSAS, thinning in some posterior ocular tissues was observed. Although patients with severe OSAS may experience clinical recovery, we recommend that they would be followed up in terms of ocular ischemic injury.

Uric acid as a potential mediator of cardiovascular morbidity in obstructive sleep apnea syndrome.

BACKGROUND AND AIMS: Obstructive sleep apnea (OSA) is now considered as an independent risk factor for cardiovascular (CV) disease. Although uric acid is increasingly being implicated in CV morbidity and mortality, no study attempted to determine independent role of uric acid in CV morbidity of OSA patients. We aimed to assess the role of serum uric acid as a potential mechanism of CV morbidity in a nonselected cohort of OSA patients. METHODS: This was a cohort study in which patients who had undergone a formal sleep study for diagnosis of OSA were recruited. Included patients were grouped according to apnea-hypopnea index (AHI) as mild, moderate and severe OSA. Patients with AHI<5 served as control group. Patients were interrogated as to cardiovascular morbid conditions which included prior history and an established diagnosis of coronary artery disease, cerebrovascular accident, congestive heart failure due to coronary artery disease and arrhythmias. RESULTS: 436 OSA patients included (72 controls, 97 with mild, 75 with moderate, and 192 with severe OSA). The severe group also had higher serum uric acid level compared with the control and other OSA groups. Linear regression showed that the Ln uric acid was positively associated with Ln AHI score. In unadjusted logistic regression, severe OSA was associated with higher odds of a cardiovascular event, OR=2.81 (1.307-6.041), p=0.0081 while the other categories of sleep apnea were not. However, severe OSA was no longer significant after adjusting for age, gender, diabetes mellitus status, hypertension status, BMI, and smoking, OR=1.882 (0.826-4.287), p=0.1322. Uric acid was significantly higher in those who had a cardiovascular event even in the mild, moderate and severe OSA groups. CONCLUSION: Hyperuricemia is strongly associated with cardiovascular disease in OSA patients. This strong relationship persists even after controlling for well-known traditional risk factors for cardiovascular disease.