Chronic cough and obstructive sleep apnoea in a sleep laboratory-based pulmonary practice

Tsai-Yu Wang,Horng-Chyuan Lin,Po-Jui Chang,Chun-Hua Wang,Pai-Chien Chou,Wen-Te Liu,Fu-Tsai Chung,Ting-Yu Lin,Shu-Chuan Ho,Yung-Lun Ni,Han-Pin Kuo,Shu-Min Lin,Chih-Teng Yu,Yu-Lun Lo,Chih-Hsi Kuo

doi:10.1186/1745-9974-9-24

Abstract

BackgroundObstructive 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.MethodsPatients 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.ResultsA 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).ConclusionThe 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.

Highlights

The incidence of chronic cough ranges from 9% to 33% of the adult population [1,2]
The percentage of chronic cough was significantly higher in the Obstructive sleep apnoea (OSA) group compared to the Non-OSA group (39.4% vs. 12.5%, p = 0.005)
The incidence of Gastro-oesophageal reflux disease (GERD) was significantly higher in the OSA group, while the incidence of upper airway cough syndrome (UACS) and asthma was similar between the two groups

Summary

Introduction

The incidence of chronic cough ranges from 9% to 33% of the adult population [1,2]. The aetiologies of 12% to 42% of coughs are unexplained despite thorough evaluation [4]. It is important to explore other possible aetiologies for chronic cough. A recent study reported four patients with unexplained chronic cough who were found to have obstructive sleep apnoea (OSA). 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

Objectives

Methods

Results

Conclusion