The validity and precision of the Leicester Cough Questionnaire in COPD patients with chronic cough.
BACKGROUND
A validated instrument to assess the effects of chronic cough on health status in patients with chronic obstructive pulmonary disease (COPD) is currently not available. The Leicester Cough Questionnaire (LCQ) is a cough-specific health status questionnaire which is originally validated for a population of general patients presenting with chronic cough. We examined the psychometric performance of the LCQ in patients with COPD and chronic productive cough.


METHODS
Concurrent validity, internal consistency, reproducibility and responsiveness were determined. The St. George's Respiratory Questionnaire (SGRQ) and the Short Form-36 (SF-36) were used as external criteria. Questionnaires were completed at the start of the study. After 2 and 12 weeks the LCQ was repeated, together with a global rating of change.


RESULTS
In total 54 patients were included. Concurrent validity analysis showed significant correlations between corresponding domains of the LCQ and the SGRQ (r(s) -0.31 to -0.60). Corresponding domains of the LCQ and the SF-36 showed weaker correlations (r(s) 0.04 to 0.41). Internal consistency was adequate for two of the three domains (Cronbach's α 0.74 - 0.86). Test-retest reliability in stable patients was high (intraclass correlation coefficients 0.79 - 0.93). The mean difference after two weeks was 0.73 (± 1.75). Responsiveness analysis indicated that the LCQ was able to detect changes after 12 weeks.


CONCLUSIONS
The LCQ is a valid, reliable, responsive instrument to measure health status in COPD patients with chronic productive cough.


BACKGROUND
ClinicalTrials.gov: NCT01071161.
Isala klinieken, department of pulmonary diseases, Zwolle, The Netherlands. f.f.berkhof@isala.nl
Farida F
FF
Berkhof
Lisenka N
LN
Boom
Nynke E
NE
ten Hertog
Steven M
SM
Uil
Huib A M
HA
Kerstjens
Jan W K
JW
van den Berg
D000367:Age Factors; D017963:Azithromycin / Q000627:therapeutic use*; D002908:Chronic Disease; D003371:Cough / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D015203:Reproducibility of Results; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires / Q000592:standards*; D016896:Treatment Outcome
D017963:Azithromycin