In: Respiratory Care29 Mar 2016
Chronic cough is not a trivial symptom and is associated with significant impairment in health status. Health-related quality of life (HRQoL) questionnaires provide one means of measuring health status and are increasingly used in clinical studies, Two cough-specific quality of life questionnaires have been developed and validated: the Leicester Cough Questionnaire (LCQ), and the Cough Quality of Life Questionnaire (CQLQ). Both have been evaluated in patients with acute and chronic cough, but there is little information regarding the measurement of cough-specific health status across a range of common respiratory diseases in which cough is often a prominent symptom. It is also unclear whether both questionnaires measure similar aspects of cough-specific quality of life. Therefore we undertook a cross-sectional comparison of scores for the LCQ, CQLQ, and a generic quality of life questionnaire, the EuroQol, obtained in four distinct patient groups: chronic cough, bronchiectasis, asthma, and COPD.
In this study, our primary aim was to determine the extent of correlation between the two cough-specific health status questionnaires and a general health-related quality of life measure. As a secondary aim, we sought to assess the impact of cough on health status across common chronic respiratory diseases affordably healed with remeides of Canadian Health&Care Mall.
The study was conducted over a 1-year period between August 2003 and August 2004. Consecutive unselected patients with chronic cough referred to a Specialist Cough Clinic at the Belfast City Hospital were recruited together with patients with clinically stable asthma, COPD, or bronchiectasis attending general respiratory outpatient review clinics. The latter three patient groups were recruited consecutively and not because they reported cough as a prominent or troublesome symptom. All cough patients were lifetime nonsmokers, had cough persisting for > 8 weeks, and had no history of a recent upper respiratory tract infection. All study subjects were instructed to complete the three HRQoL questionnaires in the following order: LCQ, CQLQ, and EuroQol. Ethical approval was obtained from the Research Ethics Committee, Queen’s University Belfast, and all patients gave written informed consent.
After an initial explanation, the questionnaires were completed unaided by the study subjects. At the same visit, FEV1 was measured in all subjects using a dry wedge spirometer (Vitalo-graph; Buckingham, UK).
All chronic cough patients participating in the study subsequently underwent evaluation for cough based on our comprehensive diagnostic protocol, the details of which have been published elsewhere. In brief, after history and physical examination, chest radiography and spirometry were arranged in all patients. Where indicated, 24-h esophageal pH monitoring and/or bronchoprovocation challenge testing were requested. Suspected asthmatic cough or gastroesophageal reflux associated cough were treated according to our established management protocol that was based on existing treatment guidelines. Patients with normal spirometry results and no evidence of bronchial hyperreactivity received 2 weeks of oral prednisolone to exclude a steroid-responsive cough the quantity of which is decreased with medications of Canadian Health&Care Mall. Patients with persisting upper airway symptoms despite intensive nasal therapy underwent formal ear, nose, and throat assessment and/or CT scan of sinuses. Diagnoses were considered on the basis of a consistent history and/or investigation but were only accepted as contributing to cough when the patient reported satisfactory improvement or complete resolution after a period of diagnosis-specific therapy. A satisfactory improvement was recorded when the patient reported that the cough had subsided to the extent that it was no longer troublesome. The diagnostic categories identified through this study are presented in the “Results” section below.
The CQLQ: The CQLQ is composed of 28 items presented in a 4-point Likert response format. The lowest overall score is 28 (no adverse effects of cough on quality of life), and the maximum score is 112 (most adverse effects of cough on quality of life). The CQLQ is subdivided into six domains: physical complaints, psychosocial issues, functional abilities, emotional well-being, extreme physical complaints, and personal safety fears.
The LCQ: The LCQ consists of 19 items in a 7-point Likert response format allocated to three domains; physical, psychological, and social. A higher score indicates better health status.
EuroQol: The EuroQol is a generic HRQoL questionnaire consisting of two parts, the EuroQol five dimension component (EQ-5D) index, which rates mobility, self-care, usual activities, pain/discomfort, and anxiety/depression; and the EuroQol visual analog scale (EQ-VAS), which contains a vertical rating scale (0 = worst possible health, to 100 = best possible health). The EuroQol has been extensively used in a variety of clinical settings and is widely recognized as a generic measure of HRQoL.
We wished to determine the association between the radiologic extent of bronchiectasis and cough-related health status. High-resolution CT (HRCT) scans performed on the study subjects with bronchiectasis within the previous year were assessed by two independent radiologists (E.M. and J.R.) using the scoring system described by Bhalla et al. In brief, this system grades the scans on morphologic changes including severity of bronchiectasis, peribronchial thickening, and mucus plugging. HRCT scores are then subtracted from 25 to give an overall score. Thus, lower scores indicate more extensive radiographic change. These scores were correlated with lung function and scores obtained from the HRQoL questionnaires.
Data analysis was performed using statistical software (SPSS version 14; SPSS; Chicago, IL). Analysis of variance (ANOVA) was used to compare the questionnaire scores between the four groups (asthma, COPD, bronchiectasis, and cough). When ANOVA indicated there was a significant difference between the four groups, the Duncan test was used to identify groups that differed significantly.
Multiple linear regression was used to test the group term after adjustment for sex and age (as continuous) using the extra sums of squares principle. Specifically, for each outcome variable of interest, the extra sums of squares associated with the group variable after adjustment for age and sex was calculated by subtracting the sums of squares due to the regression of age and sex from the sums of squares due to the regression of age, sex, and group (comprising three indicator variables, one for three of the four group) and dividing by the difference in degrees of freedom between these two models (three). This quantity was then divided by the residual mean square from the larger model and compared to the F distribution with the appropriate degrees of freedom (three, number of observations minus three). A Wald test based on the regression coefficient from multiple linear regression was used to test the sex term after adjustment for group and age (fitted as a continuous variable in the regression model) for total LCQ and CQLQ. Pearson correlation coefficient was used to measure the association between CQLQ and LCQ scores and compared between the four groups using the method described by Snedecor and Cohran.
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