How to quantify coughing? Correlations with quality of life in chronic cough

¹ Respiratory Research Group, University of Manchester, Manchester, UK; and North West Lung Centre, University Hospital of South Manchester NHS Foundation Trust, Manchester, UK
² Respiratory Research Group, University of Manchester, Manchester, UK

^* To whom correspondence should be addressed. E-mail: Angela.Kelsall{at}manchester.ac.uk.

	Abstract

Different methods are used for quantifying coughing in sound recordings, but as yet no method has been shown to be more valid than any other. We have examined the relationships between three different units of cough and evaluated their ability to predict subjective ratings of cough and cough related quality of life.

70 subjects (mean age 55yrs (SD±11.7yrs), 73% female) with chronic unexplained cough (median duration 4.8yrs (IQR 2.5–10.1 yrs), performed fully ambulatory 24-hour sound recordings, manually counted by trained observers and quantified in (1) explosive phases, (2) cough seconds and (3) cough epochs. Subjects also completed cough visual analogue scales (VAS) and the Leicester cough questionnaire (LCQ).

All units of cough were strongly correlated; explosive phases and cough seconds correlated slightly more strongly than cough seconds with cough epochs or explosive phases with cough epochs (r=0.99 p=<0.001, r=0.92, p=<0.001 and r=0.90, p=<0.001, respectively). LCQ scores correlated moderately with explosive phases and seconds (r= -0.53, p<0.001 and r= -0.53, p<0.001); epochs correlated slightly less well (r= -0.46, p<0.001). Cough VAS scores showed a similar pattern.

Explosive phases and seconds are interchangeable units of cough, moderately related to subjective measures and cough related quality of life; epochs are a less satisfactory alternative.

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				A Kelsall, S Decalmer, K McGuinness, A Woodcock, and J A Smith Sex differences and predictors of objective cough frequency in chronic cough Thorax, May 1, 2009; 64(5): 393 - 398. [Abstract] [Full Text] [PDF]