title: Chronic cough and obstructive sleep apnoea in a sleep laboratory-based pulmonary practice.
abstract: BACKGROUND
  Obstructive sleep apnoea (OSA) has recently been identified as a possible aetiology for chronic cough. The aim of this study was to compare the incidence of chronic cough between patients with and without OSA and the impact of continuous positive airway pressure (CPAP) treatment in resolving chronic cough.
  
  
  METHODS
  Patients referred to the sleep laboratory from January 2012 to June 2012 were retrospectively enrolled. Clinical data, treatment course and resolution of chronic cough were analysed. Specifically, gastro-oesophageal reflux (GERD), upper airway cough syndrome, asthma, apnoea-hypopnoea index and the impact of CPAP treatment on chronic cough were assessed.
  
  
  RESULTS
  A total of 131 patients were reviewed. The incidence of chronic cough in the OSA group was significantly higher than the non-OSA group (39/99 (39.4%) vs. 4/32 (12.5%), p = 0.005). Both GERD and apnoea-hypopnoea index were significantly associated with chronic cough in univariate analysis. After multivariate logistic regression, GERD was the only independent factor for chronic cough. Moreover, the resolution of chronic cough was more significant in the OSA patients with CPAP treatment compared with those not receiving CPAP treatment (12/18 (66.7%) vs. 2/21 (9.5%), p = 0.010).
  
  
  CONCLUSIONS
  The incidence of chronic cough was significantly higher in the OSA patients. In addition, CPAP treatment significantly improved chronic cough. Therefore, OSA may be a contributory factor to chronic cough.
authors.forename: Tsai-Yu
authors.initials: TY
authors.lastname: Wang
authors.affiliation: Department of Thoracic Medicine, Chang Gung Memorial Hospital and Chang Gung University, School of Medicine, 199 Tun-Hwa N, Rd,, Taipei, Taiwan. loyulun@hotmail.com.
authors.forename: Yu-Lun
authors.initials: YL
authors.lastname: Lo
authors.forename: Wen-Te
authors.initials: WT
authors.lastname: Liu
authors.forename: Shu-Min
authors.initials: SM
authors.lastname: Lin
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Lin
authors.forename: Chih-Hsi
authors.initials: CH
authors.lastname: Kuo
authors.forename: Fu-Tsai
authors.initials: FT
authors.lastname: Chung
authors.forename: Pai-Chien
authors.initials: PC
authors.lastname: Chou
authors.forename: Po-Jui
authors.initials: PJ
authors.lastname: Chang
authors.forename: Yung-Lun
authors.initials: YL
authors.lastname: Ni
authors.forename: Shu-Chuan
authors.initials: SC
authors.lastname: Ho
authors.forename: Horng-Chyuan
authors.initials: HC
authors.lastname: Lin
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Wang
authors.forename: Chih-Teng
authors.initials: CT
authors.lastname: Yu
authors.forename: Han-Pin
authors.initials: HP
authors.lastname: Kuo