ORIGINAL RESEARCH–SLEEP MEDICINE Patients with severe obstructive sleep apnea syndrome and elevated high-sensitivity C-reactive protein need priority treatment Li-Ang Lee, MD, Ning-Hung Chen, MD, Chung-Guei Huang, MS, Shih-Wei Lin, MD, Tuan-Jen Fang, MD, and Hsueh-Yu Li, MD, Taoyuan, Taiwan; and Edinburgh, United Kingdom Sponsorships or competing interests that may be relevant to con- tent are disclosed at the end of this article. ABSTRACT OBJECTIVE: To evaluate the clinical factors predicting the significantly elevated high-sensitivity C-reactive protein (hs-CRP) concentrations, defined herein as hs-CRP  3 mg/L, in adult males with untreated obstructive sleep apnea syndrome (OSAS). STUDY DESIGN: Cross-sectional study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Sixty-five consecutive male patients with newly diagnosed OSAS were enrolled to receive complete medical history review, physical examination, in-labora- tory overnight polysomnography, and hs-CRP test. The patients had no current or history of cardiovascular disease. The patients had a mean age of 38.2  9.9 years, body mass index (BMI) of 27.4  3.5 kg/m 2 , and Epworth Sleepiness Scale (ESS) of 11.3  4.6. The serum levels of hs-CRP were assessed using peripheral venous blood samples. RESULTS: Twenty-three percent of the overall patients had significantly elevated serum levels of hs-CRP. The increase of hs-CRP correlated fairly with BMI, apnea-hypopnea index (AHI), tonsil size, and ESS (r = 0.450, 0.398, 0.393, and 0.300, respec- tively; all P  0.05) after adjustment for conventional coronary heart disease risk factors. However, only the AHI could predict for significantly elevated hs-CRP after stepwise multiple linear regres- sion (R 2 = 0.251, P  0.001). CONCLUSION: Patients in this study with hs-CRP  3 mg/L were more prevalent in the severe OSAS group. This observation suggests that the severe OSAS patients need to have their cardio- vascular statuses evaluated by use of an hs-CRP screening test. © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. O bstructive sleep apnea syndrome (OSAS) is a preva- lent disorder in Taiwan. In our previous epidemiologic study, more than half of the adult subjects snored, and almost three percent had experienced apnea. 1 A growing body of evidence suggests that OSAS is associated with cardiovascular morbidity as well as mortality. 1-3 Chronic intermittent hypoxia during sleep can cause inflammation and oxidative stress and, as a result, promote vascular re- modeling, atherosclerosis, and myocardial ischemia/infarc- tion. 4,5 Therefore, accurate identification of patients with OSAS at risk for cardiovascular disease is essential. In our previous study, 1 we found that a large proportion of patients with OSAS, like individuals with cardiovascular events, 6 are associated with at least one of the conventional risk factors of coronary heart disease (CHD), including smok- ing, diabetes, hypertension, and hyperlipidemia. In addition to the above risk factors, C-reactive protein (CRP) has been used to predict CHD 7,8 and has been frequently applied as a biomarker for cardiovascular disease in OSAS patients. 9-17 CRP is one of the acute-phase proteins that increase during systemic inflammation. Patients with OSAS have increasing oxidative stress, impaired endothelium-dependent vasodilation, high blood pressure, subclinical inflammation, and elevated CRP. 4,5,9 In addition, higher CRP levels are related to increased risk of myocardial infarction, stroke, and peripheral arterial disease in otherwise healthy subjects. 18 Cur- rently, a more sensitive CRP test exists to determine heart disease risk, known as a high-sensitivity C-reactive protein (hs-CRP) assay. It is standardized, reproducible, minimally invasive, and available worldwide. Studies in the general mid- dle-aged population suggest that the risk of future CHD in- creases twofold when the level of hs-CRP rises from 1.0 mg/L (low risk) to 3.0 mg/L (high risk). 19,20 High levels of hs-CRP identify increased risk of initial cardiovascular events in CHD patients. 21 However, the effects of OSAS on serum CRP/hs- CRP levels are still unclear, possibly due to the confound- ing effects of medical comorbidity or obesity. 9,10-13 Fur- ther, the clinical prognostic value of CRP remained limited in a recent cohort study. 22 Accordingly, the rou- tine application of hs-CRP for prediction of incident cardiovascular events or monitoring of CHD risk reduc- tion in patients with OSAS is still questionable. Received December 7, 2009; revised March 16, 2010; accepted April 1, 2010. Otolaryngology–Head and Neck Surgery (2010) 143, 72-77 0194-5998/$36.00 © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2010.04.001