C-reactive protein improves the ability to detect cardiometabolic risk in mild-to-moderate obstructive sleep apnea

Obstructive sleep apnea (OSA), particularly in the mild-to-moderate range, affects up to 40% of the adult general population. While it is clear that treatment should be pursued in severe cases of OSA, when and how to best treat OSA in the mild-to-moderate range remains complicated, despite its high prevalence. The aim of this study was to compare the relative utility of apnea/ hypopnea index (AHI) versus a biomarker of inflammation, C-reactive protein (CRP), in identifying the presence and severity of hypertension and hyperglycemia. Middle-aged (n = 60) adults with mild-to-moderate OSA (AHI between 5 and 29 events per hour) underwent 8-h polysomnography, a physical examination including measures of blood pressure and body mass index, and a fasting morning blood draw for glucose and CRP. CRP levels were associated with greater odds for having hypertension and hyperglycemia compared to AHI. Receiver-operating characteristics (ROC) curves revealed that adding CRP to standard clinical factors (age, sex, and BMI) yielded moderately good to strong risk models for the disorders (AUC = 0.721 and AUC = 0.813, respectively). These preliminary findings suggest that including a measure of CRP improves the ability for clinicians to detect cases of mild-to-moderate OSA with true cardiometabolic risk, with implications in improving prognosis and treatment within this clinically gray area.