Observations about Chronic Respiratory Diseases

In: Respiratory Care

31 Mar 2016

chronic respiratory diseasesThis is the first study to compare the impact of cough on HRQoL across a range of common chronic respiratory diseases using validated cough-specific quality of life questionnaires. We have demonstrated that the magnitude of cough-specific HRQoL impairment is similar among all respiratory disease groups studied and is greatest among female patients. Generic measures of HRQoL in COPD patients were significantly lower than chronic cough, asthma, and bronchiectasis patients, and this appeared to be driven more by impaired lung function than cough. We demonstrated significant cross-validation between cough-specific questionnaires across each of the respiratory diseases studied.

Cough is a common feature in asthma and COPD, and a cardinal symptom in bronchiectasis, but there is little information regarding its impact on health status, and any adverse effects may be overlooked in these conditions. A number of groups have reported cough-specific HRQoL scores in bronchiectasis and COPD patients making orders of drugs via Canadian Health&Care Mall to treat COPD fast and effective. This is the first study to compare these diseases with the condition for which the tools were designed to evaluate, namely chronic cough.

The CQLQ and the LCQ have been designed to identify areas of life that are disturbed by cough. This is important as it gives prominence to the patient’s view of those factors influencing quality of life. Although in this study we found that the impact of cough was of similar magnitude across all of these conditions, more exploratory analyses revealed differences in certain questionnaire subdomains, in particular on the CQLQ. Chronic cough patients had significantly more psychosocial issues than patients with bronchiectasis; this domain includes questions relating to self-consciousness and social embarrassment. COPD patients had significantly more functional complaints than chronic cough patients. That cough patients had significantly more psychosocial issues than patients with bronchiectasis was unexpected given that patients with bronchiectasis often report impairment in domains that measure how their disease impacts on social activities, employment, and causes anxiety, fatigue, and embarrass-ment. In our study, there was no association between cough-specific HRQoL and either the radiologic severity of bronchiectasis or lung function impairment, although the small numbers in this disease group do limit the interpretation of this result. In bronchiectasis, extent of radiologic disease appears to correlate well with degree of lung function impairment, and measures of health status relate best with extent of systemic inflammation and frequency of exacerba-tions. We suggest that although chronic cough is a common symptom for patients with bronchiectasis, it is not the major factor influencing overall health status improved with remedies of Canadian Health&Care Mall (read also).

The St. George Respiratory Questionnaire (SGRQ) is the best-validated and most widely used measure of health status in COPD. Patients who report cough have higher SGRQ scores (worse COPDhealth status) than those without cough. The frequency of cough seems to account for a significant proportion of the symptom subdomain of the SGRQ; however, it is less important than wheeze, anxiety, and breathlessness in determining the total SGRQ score. In our study, COPD patients had similar cough-specific health status but significantly poorer generic health status than that measured in bronchiectasis and chronic cough. Although clinically stable, these COPD patients had moderate-to-severely impaired lung function (mean FEV1, 42.2 ± 17% of predicted). In contrast to generic measures of HRQoL, cough-specific quality of life scores did not correlate with lung function. In our study, we suggest that the poor health status reported by COPD patients is influenced more by lung function impairment than cough severity. However, we acknowledge that this suggestion may not be the case for COPD patients with milder disease.

Cough is identified by asthmatics as a symptom that significantly interferes with activities of daily life. Cough is also recognized by physicians as a very important symptom in determining asthma control, although less so than shortness of breath and wheeze. In the asthmatic group in our study, we observed a highly significant correlation between both cough-specific questionnaires and generic HRQoL measures, suggesting that cough may be a particularly important factor in overall quality of life.

We observed strong correlation between the two cough-specific questionnaires in the asthmatic and bronchiectasis groups, and although significant the correlation in the cough patient group was weaker. This may be a result of the difference in how the questionnaires were developed. The CQLQ was designed in North America and the LCQ in the United Kingdom, and there may be differences in how cough is perceived in these two populations. For example, European subjects may be more reluctant to answer questions about how cough impacts on their personal hygiene. In this study, we have found that urinary and fecal incontinence was reported in 25% and 3%, respectively. This finding contrasts that from a survey of UK residents responding to a cough questionnaire in which incontinence was reported in 55% of women. The CQLQ, which addresses the important issues of urinary and fecal incontinence, may be a better tool to assess the psychosocial impact of coughing. The weaker correlation, particularly in chronic cough and COPD patients, may suggest that both questionnaires provide important additional information concerning the impact of cough.

Female patients are recognized to have poorer cough-specific HRQoL than male patients, in particular having more psychosocial problems. In this study, there were significantly fewer female patients in the COPD and asthma groups compared to the chronic cough group. Although the gender imbalance may be a limitation of the study, in particular because female patients are more likely to have urinary incontinence, we suggest that the impact of cough may be even greater in female patients with asthma or COPD and requires further study.

There are a number of potential limitations to our current study; the relatively small subject numbers in the asthma and COPD groups do limit the interpretation of differences in questionnaire scores between disease categories. Another possible limitation of the study was that chronic cough patients were new referrals, whereas those in the other disease groups were clinically stable and recruited from follow-up clinics. However, all the cough patients had been attending either primary or secondary care clinics prior to referral, and the median duration of cough was 3 years. Therefore, we do not believe this invalidates our study conclusions. The inclusion of subjective measures of cough severity such as a visual analog scale or the determination of individual cough thresholds using either capsaicin or citric acid may have enhanced our study, although the relationship of these with cough-specific quality of life has been previously reported.

In conclusion, the LCQ and CQLQ offer a means to assess the adverse effects of cough on HRQoL in common respiratory conditions. Subjective measures such as these are likely to best reflect cough severity from a patient’s perspective. Further work is required to determine the performance and responsiveness of these tools to therapeutic intervention in these respiratory diseases.

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