Influence of Gender on C-Reactive Protein, Fibrinogen, and Erythrocyte Sedimentation Rate in Obstructive Sleep Apnea

Inflammation is one of the pathophysiological pathways suggested for the development of cardiovascular disease in obstructive sleep apnea (OSA). The recurrent nocturnal episodes of hypoxia/reoxygenation observed in patients with OSA appear to be partly responsible for the systemic inflammatory response. The aim of this study was to investigate the role of inflammation by measuring the C-reactive protein (CRP) and fibrinogen levels, and erythrocyte sedimentation rate (ESR) in the OSA according to gender. This study included 139 apparently healthy subjects with newly diagnosed OSA and 27 control subjects who underwent overnight polysomnography and routine blood tests. Levels of inflammatory markers (CRP, fibrinogen, and ESR) were determined from the blood samples taken in the morning. The levels of CRP and fibrinogen were significantly higher in patients than in controls (p<0.0001 and p=0.001, respectively). Fibrinogen and ESR were significantly higher in the female patients than in the male patients (p<0.0001). In female patients, CRP and ESR correlated with time spent at oxygen saturation (T%SaO2)<90 (R=0.327, p=0.029 and R=0.301, p=0.05, respectively), T%SaO2<85 (R=0.482, p=0.001 and R=0.409, p=0.006, respectively), oxygen desaturation index (ODI) (R=0.298, p=0.047 and R=0.340, p=0.026, respectively), lowest oxygen saturation (SaO2) (R=-0.293, p=0.051 and R=-0.374, p=0.013, respectively), mean SaO2 (R=-0.408, p=0.005 and R=-0.385, p=0.011, respectively). In male patients, CRP correlated with T%SaO2<90 (R=0.267, p=0.009), T%SaO2<85 (R=0.279, p=0.006), mean SaO2 (R=-0.284, p=0.006) and fibrinogen correlated with T%SaO2<90 (R=0.282, p=0.028), and mean SaO2 (R=-0.252, p=0.05). In conclusion, increased values of systemic inflammatory markers and their correlations with sleep data observed in our study support other studies suggesting the possible involvement of inflammation in OSA. As this correlation is more apparent in female patients then the males, it suggests that there may be a stronger relation between OSA development and inflammation in females. Higher levels of CRP, fibrinogen, and ESR may result from the combined interactions of obesity, metabolic syndrome (MetS) and nocturnal hypoxia.