Red blood cell distribution width in Obstructive Sleep Apnea Syndrome and its association with cardiovascular disease

Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular disease (CVD). Red blood cell distribution width (RDW) is reported as a novel marker of cardiovascular disease (CVD) risk. We aimed to investigate the correlation of RDW level with the severity of Obstructive Sleep Apnea Syndrome (OSAS) defined with the apnea-hypopnea index (AHI) and to study the relationship between RDW and CVD in OSAS.

From retrospective analyses of patients admitted to our department for polygraphy between January 2018 and January 2020, OSAS patients with complete medical records and hemogram analyses were evaluated.

The study population consisted of 160 patients (101 females/59 males). The mean age was 52.32 ± 10.83 years. RDW correlated positively with the apnea hypopnea index (AHI) (r=0.392; p < 0.0001) and C-reactive protein (CRP) (r = 0.3, p < 0.001). RDW and CRP were significantly higher in patients with CVD than whom without CVD (p < 0.0001). In multivariate analysis, the independent predictors of CVD in OSAS were RDW (p < 0.0001; OR=3.095; CI: 1.69-5.66), CRP (p=0.046; OR=1.136; CI: 1.002-1.287) and age (p=0.013; OR=1.085; CI: 1.017- 1.157). The cut-off level for RDW with optimal sensitivity and specificity was calculated as 14.45 with sensitivity of 81% and specificity of 75%.

The findings of this study suggest that RDW, a simple, relatively inexpensive and universally available marker could have the ability to predict CVD in OSAS.