The Significance of the Relative Lymphocyte Count as an Independent Predictor of Cardiovascular Disease in Patients with Obstructive Sleep Apnea Syndrome

OBJECTIVE The aim of this study was to determine whether or not relative lymphocyte count (RLC) is associated with cardiovascular disease (CVD) in patients with obstructive sleep apnea syndrome (OSAS). SUBJECTS AND METHODS In this study, 141 patients diagnosed with OSAS using polysomnography were enrolled. Patients were classified according to the severity of OSAS as determined by the apnea-hypopnea index (AHI) and presence of CVD. Lymphocyte count and other hematological parameters at complete blood count were determined and compared between patients with and without CVD. Multivariate regression analysis was used to estimate the associated factors for presence of CVD. RESULTS Absolute and relative lymphocyte counts were lower in the OSAS patients with CVD compared to those without CVD (mean absolute lymphocyte counts: 2.0 × 103 vs. 2.5 × 103 µl, p = 0.004, and mean RLC: 28.3 vs. 33.9%, p = 0.001, respectively). OSAS patients with CVD (14.2) had higher red cell distribution width values than the patients without CVD (13.4) (p = 0.005). Multivariate analysis identified RLC as an independent predictor of CVD in patients with OSAS (odds ratio = 0.9, 95% CI: 0.85-1.0, p = 0.042). CONCLUSION RLC was identified as an independent predictor of CVD in patients with OSAS. Since RLC is a widely available diagnostic tool with no additional costs over the routinely performed complete blood count, it can be used for predicting CVD in patients with OSAS.