Relationship Between Obstructive Sleep Apnea Severity and Serum Endocan Levels in Patients With Hypertension

Abstract

Background Obstructive sleep apnea (OSA) is common in middle-aged adults and has been associated with various cardiovascular disorders; endothelial dysfunction may play a role in the pathogenesis of these disorders in patients with OSA. Endothelial cell specific molecule-1 (endocan) is a marker of vascular pathology, which is correlated with endothelial dysfunction. This study investigates the relationship between serum endocan levels and OSA severity in patients with hypertension. Methods A retrospective review included 48 patients with OSA and hypertension but without conventional cardiovascular risk factors, and 67 patients with OSA who did not have hypertension. The correlation between serum endocan levels and the apnea-hypopnea index (AHI) was investigated in both groups. Results There was a significant correlation between the serum endocan level and the AHI in patients with OSA and hypertension (r = 0.308; P = .033), but there was no such correlation in patients without hypertension (r = 0.193; P = .118). However, when both groups were combined (ie, all patients with OSA), there was a significant correlation between serum endocan levels and the AHI (r = 0.228; P = .014). On multiple logistic regression analysis, endocan levels were independent predictors of OSA severity in patients with OSA and hypertension (P = .029). Conclusion In patients with OSA and hypertension, serum endocan levels are significantly correlated with the AHI. Measurement of endocan may have a place in evaluating patients with OSA and hypertension for adverse cardiovascular events, and they may even help to guide OSA therapy for these patients.