Importance of laboratory parameters in patients with obstructive sleep apnea and their relationship with cardiovascular diseases

BACKGROUND: Ostructive sleep apnea (OSA) is an independent risk factor for the development of cardiovascular events. Platelet activation and inflammation are the mechanisms involved in the association between OSA and cardiovascular disease (CVD). The markers of platelet activation and inflammation are the mean platelet volume (MPV), platelet-lymphocyte ratio (PLR), red cell distribution width (RDW), neutrophil- lymphocyte ratio (NLR). We aimed to define the association of NLR, PLR, RDW, and MPV with the severity of disease and the presence of CVD. METHODS: This study consisted of 300 patients who were admitted to the sleep laboratory. The patients were classified according to their apnea- hypopnea index (AHI) scores as OSA negative (Group A: AHI<5), mild (Group B: AHI: 5-15), moderate (Group C: AHI=15-30), and severe OSA (Group D: AHI >30). RESULTS: There were no significant differences in the NLR, PLR, and MPV among the groups (P>.05); only RDW differed significantly (P=.04). RDW was significantly higher in patients with than without risk factors for CVD [15.6% (15.4-15.7) vs 15.3% (15.1-15.3), respectively; P=.02]. CONCLUSIONS: NLR, PLR, MPV, and RDW are widely available and easily obtained from a routinely performed hemogram. Among these laboratory parameters, only RDW can demonstrate the reverse consequences of OSA-associated comorbidities, because vascular damage due to systemic inflammation is an important underlying mechanism in these diseases. RDW might be used as a marker of the response and patient compliance with continuous positive airway pressure treatment.