Platelet-lymphocyte ratio is an independent predictor for cardiovascular disease in obstructive sleep apnea syndrome.

There is a strong relationship between obstructive sleep apnea syndrome (OSAS) and cardiovascular disease (CVD). Chronic intermittent hypoxia, inflammation, oxidative stress, and endothelial dysfunction may constitute etiologic mechanisms, linking OSAS to CVD. Inflammation play an important role in the development of CVD. Platelet-lymphocyte ratio (PLR) is a new biomarker showing inflammation. No previous study has ever investigated the association between PLR, CVD and OSAS severity in patients with OSAS. This study was designed to investigate the association between PLR and CVD in patients with OSAS, and relationship between severity of OSAS, polysomnographic parameters and PLR. This was a cohort study in which patients who had undergone a full night polysomnoraphy for diagnosis of OSA were recruited. Patients were divided according to their apnea-hypopnea index (AHI) scores into OSAS negative (Group 1: AHI < 5), mild (Group 2: AHI, 5-15), moderate (Group 3:AHI,15-30), and severe OSAS (Group 4: AHI > 30) groups. The presence of heart failure, coronary artery disease or arrhythmia was defined as CVD. A total of 424 patients were included in this study. There were 57, 93, 82, and 192 patients in Groups 1, 2, 3, and 4, respectively. PLR were significantly different between groups (Group 1: 87.38; Group 2: 95.07; Group 3: 97.01, Group 4: 126.9, P < 0.05). PLR were significantly correlated with AHI, oxygen desaturation index, average and minimum O2 saturation values (P < 0.05). Values of PLR were significantly higher in patients with CVD compared with those without. Multiple regression analysis demonstrated that PLR is an independent predictor of CVD. PLR cut-off value for demonstrating the presence of CVD is higher than 108.56. In the light oh findings, PLR is strongly associated with the severity of OSAS and cardiovascular disease in OSAS patients. PLR might be used as a biomarker to predict CVD in OSAS patients.