Red Cell Distribution Width in Patients with Obstructive Sleep Apnea Syndrome

Red cell distribution width (RDW) has been shown to be associated with adverse outcomes in left-sided heart failure, pulmonary hypertension, and in patients in the ICU. However, the role of RDW is unknown in patients with obstructive sleep apnea syndrome (OSAS), especially in OSAS patients with cardiovascular diseases. One hundred thirty-seven patients were investigated by polysomnography (PSG) for OSAS. The patients were classified as a control group or as the OSAS group according to the apnea-hypopnea index (AHI). The RDW, hemoglobin level, and mean corpuscular volume (MCV) were determined. C-reactive protein (CRP) levels were measured. The RDW values were higher in the OSAS group than in the controls [13.6% (12-23%) vs. 12.9% (11.7-14.5%), p = 0.003]. The RDW values were higher in patients with cardiovascular diseases [13.7% (11.7-23.2%) vs. 13.2% (12-16.9%), p = 0.001]. RDW a parts per thousand yen 13.6% (odds ratio [OR] = 1.5 [95% CI = 1.0-2.0], p = 0.014) was found to be associated with increased risk for cardiovascular disease in patients with OSAS on multivariate analysis. It was also shown that there was a significant correlation between the RDW and the AHI (r = 0.272), age (r = 0.362), mean SaO(2) (r = 0.375), systolic pulmonary artery pressure (r = 0.435), and CRP level (r = 0.275) in study population. RDW is a newly recognized and widely available diagnostic tool with no additional cost over the routinely performed hemogram. RDW is independently associated with cardiovascular disease in patients with OSAS in our cross-sectional study.