Clinical trial NCT03172130: Sham CPAP vs. Straight CPAP for Chronic Cough
Official title: Prospective Study of Efficacy of Sham CPAP vs. Straight CPAP on Cough Intensity in Patients With Chronic Cough
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Chronic Cough
OSA
Keywords: Obstructive Sleep Apnea
CPAP
Lead sponsor: University of Utah
Sponsor class: OTHER
First posted: 2017-06-01
Enrollment: 22
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: Chronic cough is an important clinical problem in primary care and sub-specialty practice. Besides the distress experienced by patients with chronic cough, significant healthcare resources are expended to understand the role of gastroesophageal reflux, asthma and post-nasal drip in understanding their contribution to cough.

Obstructive sleep apnea (OSA) is common in patients with chronic cough. More importantly, treatment of OSA with continuous positive airway pressure (CPAP) has led to improvement in cough for chronic cough patients. Mechanisms by which OSA therapy with CPAP can improve cough includes beneficial effects on reflux and airway inflammation.

The aim of this study is to definitively establish that CPAP therapy for treatment of OSA in chronic cough patients improves cough. While these patients with chronic cough are not routinely screened and treated for OSA, this study aims to evaluate these chronic cough patients with screening questionnaires for OSA and if necessary with polysomnography and randomize them to either CPAP or sham CPAP for 6 weeks.


Eligibility criteria: Inclusion Criteria:

* Cough of more than 2 month duration
* Not active smoker with history of stoppage of smoking for more than 6 months
* Evaluation and treatment by other providers for suspected gastroesophageal reflux disease (GERD), upper airway cough syndrome (UACS), or cough-variant asthma (CVA) for at least 1 month
* Normal chest radiography or computed tomography (CT) scans (patients with up to 2 lung nodules less than 3 mm will be allowed if there is no history of malignancy elsewhere)
* Normal spirometry with predicted diffusing capacity of the lung for carbon dioxide (DLCO) more than 50% predicted. Pulmonary Function Test criteria: no evidence of airflow limitation (FEV1/FVC \> 0.7) or significant chest restriction (FVC \> 70% predicted) with predicted DLCO more than 50% predicted

Exclusion Criteria:

* Pregnancy
* Recent pneumonia (less than 6 months)
* Congestive heart failure, acute or chronic renal disease, jaundice or chronic liver disease, pulmonary embolism, stroke or neurodegenerative disease, malignancy
* Use of supplemental oxygen or positive airway pressure therapy (if patients have been diagnosed with obstructive sleep apnea in the past but were non-compliant with positive airway pressure therapy, they will not be excluded)
* Use of opiates for cough suppression (opiate use for pain suppression can be included)
* Alcoholism, drug dependence (including chewing tobacco) or illicit drug use
* Esophageal cancer or laryngeal surgery
* Craniofacial abnormalities that preclude CPAP placement

Primary outcomes:
measure: Change in Leicester Cough Questionnaire Score
timeFrame: Baseline and 6 weeks
Secondary outcomes:
measure: Change in Cough Frequency
timeFrame: Baseline and 6 weeks
measure: 8 Isoprostane Level in Exhaled Breath Condensate
timeFrame: Baseline and 6 weeks
measure: Interleukin-8 (IL-8) Level in Exhaled Breath Condensate
timeFrame: Baseline and 6 weeks
measure: Nitrite/Nitrate (NOX) Level in Exhaled Breath Condensate
timeFrame: Baseline and 6 weeks
measure: Hydrogen Peroxide (H2O2) Level in Exhaled Breath Condensate
timeFrame: Baseline and 6 weeks
measure: Change in Leukotriene B4 (LTB4) Level in Exhaled Breath Condensate
timeFrame: Baseline and 6 weeks
measure: Change in Gastroesophageal Reflux Disease Quality of Life (GERD-QoL) Questionnaire Score
timeFrame: Baseline and 6 weeks
Other outcomes:
Locations:
city: Salt Lake City
country: United States
facility: University of Utah
state: Utah
Study officials:
affiliation: University of Utah
name: Krishna Sundar, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Sundar KM, Willis AM, Smith S, Hu N, Kitt JP, Birring SS. A Randomized, Controlled, Pilot Study of CPAP for Patients with Chronic Cough and Obstructive Sleep Apnea. Lung. 2020 Jun;198(3):449-457. doi: 10.1007/s00408-020-00354-1. Epub 2020 Apr 30.