title: Red Cell Distribution Width in Obstructive Sleep Apnea.
abstract: BACKGROUND
  Red cell distribution width (RDW) describes heterogeneity in the size of red blood cells. An increase in RDW has been associated with excess mortality in heart failure and other chronic diseases. Since there is an increased risk of cardiovascular morbidity and mortality in obstructive sleep apnea (OSA), it is possible that these patients have a high RDW.
  
  
  METHODS
  We recruited subjects aged 18 to 60 years referred to the sleep-disordered breathing unit for suspected OSA. Subjects with any comorbidity were excluded. Apnea-hypopnea index (AHI) was calculated from the respiratory polygraphy. The RDW was obtained from the complete blood count. Changes in RDW after one year of treatment with continuous positive airway pressure (CPAP) were determined.
  
  
  RESULTS
  We included 34 healthy subjects and 138 with OSA, aged 40.5±9.8 and 45.6±9.2 (P=.004) years, respectively. The RDW was higher in subjects with OSA compared to healthy subjects: 13.40 (12.40 to 14.40) vs. 13.15 (12.07 to 14.23) (P=.036). AHI showed a positive independent relationship with RDW in both the whole population (r=0.223; P=.002) and the OSA group (r=0.231; P=.005). No significant changes were found in RDW after one year of CPAP therapy.
  
  
  CONCLUSIONS
  RDW increase in patients with OSA is directly associated with severity, although levels are not modified by the effective treatment of OSA with CPAP.
authors.affiliation: Servicio de Neumología, Hospital Universitario Miguel Servet, Zaragoza, España. Electronic address: ericaleonsubias@gmail.com.
authors.forename: Erica
authors.initials: E
authors.lastname: León Subías
authors.affiliation: Servicio de Neumología, Hospital Universitario Miguel Servet, Zaragoza, España.
authors.forename: Sara
authors.initials: S
authors.lastname: Gómara de la Cal
authors.affiliation: Servicio de Neumología, Hospital Universitario Miguel Servet, Zaragoza, España.
authors.forename: José María
authors.initials: JM
authors.lastname: Marin Trigo
mesh_terms: D000293:Adolescent; D000328:Adult; D004909:Erythrocyte Indices; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000097:blood*; D055815:Young Adult
keywords: Ancho de distribución eritrocitaria; Apnea obstructiva del sueño; Biomarcador; Biomarker; Obstructive sleep apnea; Red cell distribution width