Clinical trial NCT00451841: Exhaled Breath Condensate pH in Patients With Cough Caused by Gastroesophageal Reflux
Official title: Exhaled Breath Condensate pH in Patients With Cough Caused by Gastroesophageal Reflux
Study type: OBSERVATIONAL
Overall status: TERMINATED
Conditions: Cough
Gastroesophageal Reflux
Keywords: Cough
Gastroesophageal reflux
Exhaled breath condensate
Lead sponsor: University of Massachusetts, Worcester
Sponsor class: OTHER
First posted: 2007-03-26
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Adult patients evaluated for cough in the Lung and Allergy Center of Umass Memorial Medical Center

Brief summary: Cough is the most common complaint for which patients seek medical attention in the United States, accounting for approximately 1 billion dollars in health care expenses annually. Gastroesophageal reflux disease (GERD) is the sole cause of chronic cough in up to 20-40% of all cases. The majority of these patients with GERD-induced cough have no classic "heartburn" symptoms, so this important cause of cough can thus be difficult to detect.

Our hypothesis is that changes in exhaled breath condensate (EBC) pH can be used as a sensitive and non-invasive marker to identify subjects with cough caused by acid reflux.

Detailed description: Gastroesophageal reflux disease (GERD) is the sole cause of chronic cough in up to 20-40% of all cases, and majority of these patients with GERD-induced cough have no classic "heartburn" symptoms. This important cause of cough can thus be difficult to detect. Non-invasive radiologic tests for GERD such as barium swallow is imperfectly sensitive in subjects with GERD-induced cough. The 24 hour pH probe, which continuously monitors esophageal pH and can correlate cough events with reflux events, is considered to be the gold standard test. However, this test is expensive, invasive, and not universally available.

The goal of the current study is to compare simultaneous measurements of esophageal pH with exhaled breath condensate pH after cough episodes, in patients with symptomatic cough. The cause of cough will be determined by a standard protocol, which includes 24 hour pH probe studies, and assessment for asthma, upper airway causes and sinus disease, and medication effects. All subjects will undergo 24 hour pH monitoring. During this monitoring period, they press an event button on the pH recording device to indicate a cough episode. After six such events, they will immediately perform an EBC collection, and EBC pH will subsequently be analyzed. Differences between pH changes in the group with cough cause by GERD will be compared to pH measurements in the group with cough but no GERD, to determine the sensitivity and specificity of pH changes for discriminating between the two groups, and optimal threshold values for pH changes in EBC.

Eligibility criteria: Inclusion Criteria:

* age \> 18 years old
* able to speak and read English
* chronic cough

Exclusion Criteria:

* Cigarette smoking within the past 6 months, or greater than 10 pack year history of prior smoking
* Any self-reported or clinically diagnosed form of active lung disease, including asthma and emphysema
* Symptoms of persistent rhinitis within the past three months
* Dysphagia
* Symptoms of acute viral upper respiratory tract infection or sinusitis within one month of entry into the study
* Pregnancy - based on self report
* Abnormal chest radiograph

Primary outcomes:
measure: Sensitivity of esophageal PH changes
timeFrame: 24 hours
Secondary outcomes:
Other outcomes:
Locations:
city: Worcester
country: United States
facility: UMass Memorial Medical Center, University Campus
state: Massachusetts
Study officials:
affiliation: University of Massachusetts, Worcester
name: Stephen Krinzman, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Niimi A, Nguyen LT, Usmani O, Mann B, Chung KF. Reduced pH and chloride levels in exhaled breath condensate of patients with chronic cough. Thorax. 2004 Jul;59(7):608-12. doi: 10.1136/thx.2003.012906.
citation: Hunt J. Exhaled breath condensate pH: reflecting acidification of the airway at all levels. Am J Respir Crit Care Med. 2006 Feb 15;173(4):366-7. doi: 10.1164/rccm.2512001. No abstract available.
citation: Horvath I, Hunt J, Barnes PJ, Alving K, Antczak A, Baraldi E, Becher G, van Beurden WJ, Corradi M, Dekhuijzen R, Dweik RA, Dwyer T, Effros R, Erzurum S, Gaston B, Gessner C, Greening A, Ho LP, Hohlfeld J, Jobsis Q, Laskowski D, Loukides S, Marlin D, Montuschi P, Olin AC, Redington AE, Reinhold P, van Rensen EL, Rubinstein I, Silkoff P, Toren K, Vass G, Vogelberg C, Wirtz H; ATS/ERS Task Force on Exhaled Breath Condensate. Exhaled breath condensate: methodological recommendations and unresolved questions. Eur Respir J. 2005 Sep;26(3):523-48. doi: 10.1183/09031936.05.00029705.