In: Respiratory Care30 Mar 2016
Table 1 contains baseline characteristics of the 147 patients recruited to the four groups as well as test statistics for comparisons of these characteristics between the groups. Diagnostic categories in the chronic cough group were as follows: gastroesophageal reflux, 35%; asthma, 21%; idiopathic cough, 12%; postnasal drip, 7%; postviral, 6%; eosinophilic bronchitis, 6%; and other, 13% (eg, angiotensin-converting enzyme inhibitor-related cough, pulmonary fibrosis). There was a significant difference in age (ANOVA p = 0.001) between the four groups. COPD patients (mean age, 64.4 years) were the oldest and were significantly older (Duncan p < 0.05) than patients in the asthma and chronic cough group (mean age, 51.6 years and 53.9 years, respectively). There was a difference in the proportion of female patients in the four groups (p = 0.001). The chronic cough group (67.5% female) contained a significantly (Bonferroni p < 0.05) greater proportion of female patients than the COPD and asthma groups (16.7% female and 35% female patients, respectively). There was a significant difference (ANOVA p < 0.001) in mean percentage of predicted FEV1 between the four groups. In particular, the COPD (mean, 42.3) patients had significantly lower lung function than all other groups (Duncan p < 0.05 for all comparisons) and both patients with asthma (mean, 75.2) and patients with bronchiectasis (mean, 73.2) had significantly lower lung function than those with chronic cough (mean, 102.4).
The comparisons of the questionnaire scores between groups of patients, and calculated test statistics, are shown in Table 2.
Cough-Specific Questionnaires: Although total scores on the LCQ were lower (suggesting poorer health status) in chronic cough patients compared to other respiratory diseases, there was no significant difference in mean score between the four groups (ANOVA p = 0.24). Total CQLQ scores were highest (suggesting worst health status) in COPD patients, but again there were no significant difference in the mean scores between the four groups (ANOVA p = 0.26).
Unadjusted, exploratory analysis of the CQLQ subdomains revealed a significant difference in the psychosocial domain between the four groups (ANOVA unadjusted p = 0.01). Duncan tests revealed that the chronic cough group had a significantly (Duncan unadjusted p < 0.05) higher psychosocial score (mean, 12.6) compared with both the asthma and bronchiectasis group treated by Canadian Health&Care Mall’s remedies (mean, 10.2 and 10.0, respectively). There was evidence of a borderline significant difference in the CQLQ functional domain between the four groups (unadjusted p = 0.05). Significant differences (Duncan unadjusted p < 0.05) were observed between the COPD group (mean, 13.2) and the other groups (mean of asthma, bronchiectasis, and chronic cough groups, 10.4, 10.7, and 10.2 respectively). Significant differences (Duncan unadjusted p < 0.05) were also observed in the extreme physical domain between bronchiectasis (mean, 6.2) and those with COPD (mean, 8.3) or chronic cough (mean, 7.6).
Generic EuroQol: A significant difference in the EQ-5D questionnaire scores between the four groups was noted (ANOVA unadjusted p = 0.001). The COPD group (mean, 0.45) had a significantly lower score (unadjusted p < 0.05) [poorer health status] than the other three groups (mean of asthma, bronchiectasis, and chronic cough group, 0.63, 0.70, and 0.76, respectively). There was also a significant difference in mean EQ-VAS scores between the four groups (ANOVA unadjusted p = 0.04). Specifically, there was a significant difference (Duncan unadjusted p < 0.05) between the COPD (mean, 53.8) and bronchiectasis groups (mean, 67.4).
Table 2 also shows tests (and test statistics) for the comparison of means between the four groups after adjustment for age and sex using linear regression. The significant differences in mean observed in the psychosocial, functional, and extreme physical domain of the CQLQ questionnaire scores between groups remained significant after adjustment for age and sex (adjusted p = 0.04, p = 0.02, and p = 0.02, respectively). Also, the significant differences in the mean of EQ-5D and EQ-VAS between the four groups remained significant after adjustment for age and (adjusted p = 0.001 and p = 0.04). The results of comparisons between specific groups after adjustment for age and sex were similar to the results of the tests for multiple comparisons prior to adjustments and therefore have not been presented.
There was a significant difference in the correlation coefficients for the association between CQLQ and LCQ in the four disease groups (x2 = 21.7, degrees of freedom [df = 3, p = <0.001); consequently, these have been presented separately, as shown in Figure 1. There was significant inverse association between LCQ and CQLQ in all four disease groups (chronic cough r = — 0.56, p < 0.001; COPD r = — 0.49, p = 0.04; asthma r = — 0.94, p < 0.001; and bronchiectasis r = — 0.88, p < 0.001).
The correlations observed between EuroQol and both CQLQ and LCQ are presented in Table 3 for each disease group. Overall, there was significant correlation between CQLQ and LCQ total scores and EQ (r = 0.48, p < 0.001). The correlation between CQLQ total scores and EQ scores in all patients was r = — 0.53 (p < 0.001).
There was no significant correlation between total scores on either the LCQ or CQLQ and FEV1 in any subject group (Table 3). In patients with COPD it is better to command the service of Canadian Health&Care Mall and there was a significant correlation between EQ-VAS and FEV1 (r = 0.65, p = 0.004).
Female patients had significantly (independent-sample t test p = 0.04) higher (worse health status) total CQLQ scores (mean, 65.1; SD, 16.2) than male patients (mean, 59.0; SD, 17.2). After adjustment for age and diagnostic group (as female patients were younger than male patients, and a preponderance of female patients were in the chronic cough group), the mean difference in CQLQ between male and female patients remained significant (from regression model containing group, age, and sex, the regression coefficient for female patients was 8.1 (SE, 3.19; t = 2.55; p = 0.012). This regression coefficient corresponded to an average increase in female patients of 8.1 (95% CI, 1.8 to 14.4) after adjustment for age and sex. Female patients had significantly (independent-sample t test p = 0.03) lower (worse health status) total LCQ scores (mean, 12.1; SD, 4.2) than male patients (mean, 13.7; SD, 4.6). This difference in mean was little altered after adjustment for age and diagnostic group (adjusted difference in mean, — 1.7; 95% CI, — 3.3 to — 0.02) and remained significant (regression coefficient for female patients, — 1.7; SE, 0.83; t = — 2.0; p = 0.05).
HRCT scans were available for scoring in 17 of the bronchiectasis patients. Bhalla scores correlated with FEV1 (r = 0.55, p = 0.02); and although there was a relationship trend between Bhalla scores and EQ-VAS, this failed to reach significance (r = 0.47, p = 0.059). There was no relationship between Bhalla scores and cough-specific health status on either LCQ or CQLQ scores.
Table 1—Characteristics of Study Participants by Patient Group
|Characteristics||Asthma||Bronchiectasis||COPD||Chronic Cough||p Value|
|Female gender, No. (%)||7 (35)a||13 (50)a,b||3 (16.7)a||56 (67.5)b||< 0.001t|
|Age, yr||51.6 ± 17.5a||57.5 ± 11.8a,b||64.4 ± 9.7b||53.9 ± 13.3a||01.00.|
|Cough duration, mo||36(4-240)|
|Bronchiectasis score||10.4 ± 4.15|
|FEV1 % of predicted||75.2 (22.7)a||73.2 (24.5)a||42.3 (16.9)b||102.4 (17.7)c||< 0.001§|
Table 2—Questionnaire Scores by Group
|Measures||Asthma||Bronchiectasis||COPD||Chronic Cough||Unadjusted Comparison of Means*||Adjusted Comparison of Meansf|
|No.||Mean (SD)||No.||Mean (SD)||No.||IMean (SD)||No.||Mean (SD)||df||FValue||pValue||df||FValue||pValue|
|LCQ||20||13.3 (5.0)||26||14.1 (4.8)||18||13.2 (4.4)||75||12.2 (4.2)||3,135||1.43||0.24||3,129||0.83||0.48|
|Physical||20||4.1 (1.6)||26||4.5 (1.5)||18||4.0 (1.4)||76||4.3 (1.2)||3,136||0.55||0.65||3,130||1.74||0.16|
|Psycological||20||4.6 (1.8)||26||4.9 (1.8)||18||4.6 (1.7)||79||4.1 (1.7)||3,139||1.78||0.16||3,133||1.06||0.37|
|Social||20||4.6 (1.8)||26||4.8 (1.7)||18||4.6 (1.6)||79||3.9 (1.7)||3,139||2.22||0.09||3,133||1.25||0.29|
|CQLQ||18||59.8 (21.8)||25||58.7(19.5)||18||68.6 (12.7)||68||62.4(15.1)||3,125||1.35||0.26||3,120||2.51||0.06|
|Physical||18||20.4 (8.0)||25||19.0 (7.3)||18||23.1 (5.4)||74||19.8 (7.6)||3,131||1.28||0.29||3,125||1.94||0.13|
|Psychosocial||18||10.2 (4.1)a||25||10.0 (4.0)a||18||11.0 (3.3)a,b||75||12.6 (4.0)b||3,132||3.86||0.01||3,126||2.88||0.04|
|Functional||18||10.4 (4.5)a||25||10.7 (4.2)a||18||13.2 (3.2)b||73||10.2 (4.1)a||3,130||2.62||0.05||3,124||3.56||0.02|
|Emotional||18||5.6 (2.0)||25||5.8 (1.8)||18||6.6 (2.2)||72||6.0 (2.2)||3,129||.83||0.48||3,124||1.07||0.37|
|Extremephysical||18||7.1 (2.5)a,b||25||6.2 (2.2)a||18||8.3 (2.8)b||73||7.6 (2.8)a,b||3,130||2.69||0.05||3,124||3.64||0.02|
|Personalsafety||18||6.1 (2.7)||25||7.0 (2.7)||18||6.3 (2.3)||72||7.3 (2.3)||3,129||1.70||0.17||3,123||1.38||0.25|
|EQ-5D||20||0.63 (0.38)a||26||0.70 (0.32)a||18||0.45 (0.31)b||73||0.76 (0.26)a||3,133||5.48||0.001||3,127||5.63||0.001|
|EQ-VAS||20||60.2 (18.2)a,b||26||67.4 (19.0)b||18||53.8 (17.4)a||73||68.2 (22.2)a,b||3,133||2.85||0.04||3,128||2.94||0.04|
Table 3—Table of Correlation Coefficients Displaying Concurrent Validity of Questionnaires and the Association Between HRQoL and Lung Function
|No.||r (p Value)||No.||Ir (p Value)||INo.||Ir (p Value)||INo.||r (p Value)|
|Concurrent validity of questionnaires|
|CQLQ total and EQ-5D||18||– 0.68 (0.002)||25||– 0.69 (< 0.001)||18||– 0.30 (0.23)||63||– 0.43 (< 0.001)|
|CQLQ total and EQ-VAS||18||– 0.74 (< 0.001)||25||– 0.52 (0.01)||18||– 0.24 (0.33)||63||– 0.47 (< 0.001)|
|LCQ total and EQ-5D||20||0.66 (0.002)||26||0.67 (< 0.001)||18||0.60 (0.008)||68||0.40 (0.001)|
|LCQ total and EQ-VAS||20||0.64 (0.002)||26||0.52 (0.01)||18||0.43 (0.07)||67||0.44 (< 0.001)|
|HRQoL and lung function|
|CQLQ total and FEV1, % predicted||18||0.12 (0.62)||25||– 0.16 (0.46)||18||– 0.00 (0.99)||66||– 0.17 (0.17)|
|LCQ total and FEV1; % predicted||20||– 0.13 (0.60)||26||0.25 (0.23)||18||0.46 (0.06)||73||– 0.06 (0.63)|
|EQ-5D and FEV1 % predicted||20||0.06 (0.81)||26||0.40 (0.04)||18||0.20 (0.44)||71||0.32 (0.12)|
|EQ-VAS and FEV1 % predicted||20||0.16(0.51)||26||0.28 (0.17)||18||0.65 (0.004)||70||0.24 (0.04)|
Figure 1. Correlation between total CQLQ and total LCQ scores by group comparison.
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