title: Neutrophil-to-lymphocyte ratio in obstructive sleep apnea; a multi center, retrospective study.
abstract: OBJECTIVE
  Systemic inflammation is important in pathophysiology of obstructive sleep apnea (OSA) and its comorbidity. Neutrophil to lymphocyte ratio (N/L ratio) is a novel inflammation index that has been shown to independently predict poor clinical outcomes. In this study, we aimed to evaluate the role of N/L ratio in OSA patients and comparing with other well-known inflammatory marker, C-reactive protein (CRP).
  
  
  METHODS
  We conducted a retrospective analysis of 481 patients with mild, moderate and severe OSA (163,158 and 160 patients, respectively) and leukocyte profiles of 80 sex-, age- and body mass index- matched healthy controls. Patients were excluded if they had underlying cancer, chronic inflammatory disease, any systemic infection, uncontrolled hypertension and diabetes mellitus, a known acute coronary syndrome, valvular heart disease, a known thyroid, renal or hepatic dysfunction.
  
  
  RESULTS
  We found that N/L Ratio in severe OSA patients was significantly higher compared with mild, moderate, OSA patients and healthy controls (p < 0.001). However, there was no difference between mild and moderate OSA patients (p = 0.636). There was also no significant difference between mild-moderate OSA patients and healthy groups (p = 0.150). CRP levels were not different in all OSA stages (p = 0.595). By Spearman correlation, there was no correlation between CRP and N/L ratio.
  
  
  CONCLUSIONS
  N/L ratio, which is quick, cheap, easily measurable novel inflammatory marker with routine complete blood count analysis, is a surrogate marker of obstructive sleep apnea severity.
authors.affiliation: Department of Pulmonary and Sleep Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. nejataltintas@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Altintas
authors.forename: E
authors.initials: E
authors.lastname: Çetinoğlu
authors.forename: M
authors.initials: M
authors.lastname: Yuceege
authors.forename: A N
authors.initials: AN
authors.lastname: Acet
authors.forename: A
authors.initials: A
authors.lastname: Ursavas
authors.forename: H
authors.initials: H
authors.lastname: Firat
authors.forename: M
authors.initials: M
authors.lastname: Karadag
mesh_terms: D002097:C-Reactive Protein / Q000378:metabolism; D015897:Comorbidity; D005260:Female; D006801:Humans; D006973:Hypertension; D007249:Inflammation / Q000503:physiopathology*; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism*; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*
chemical_list: D002097:C-Reactive Protein