Therapy for cough: where does it fall short?

Etiologies of Chronic Cough in Pediatric Cohorts: CHEST Guideline and Expert Panel Report

BACKGROUND

There is no published systematic review on the etiologies of chronic cough or the relationship between OSA and chronic cough in children aged ≤ 14 years. We thus undertook a systematic review based on key questions (KQs) using the Population, Intervention, Comparison, Outcome format. The KQs follow: Among children with chronic (> 4 weeks) cough (KQ 1) are the common etiologies different from those in adults? (KQ 2) Are the common etiologies age or setting dependent, or both? (KQ 3) Is OSA a cause of chronic cough in children?

METHODS

We used the CHEST Expert Cough Panel's protocol and the American College of Chest Physicians (CHEST) methodological guidelines and Grading of Recommendations Assessment, Development, and Evaluation framework. Data from the systematic reviews in conjunction with patients' values and preferences and the clinical context were used to form recommendations. Delphi methodology was used to obtain consensus.

RESULTS

Combining KQs 1 and 2, we found moderate-level evidence from 10 prospective studies that the etiologies of cough in children are different from those in adults and are setting dependent. Data from three studies found that common etiologies of cough in young children were different from those in older children. However, data relating sleep abnormalities to chronic cough in children were found only in case studies.

CONCLUSIONS

There is moderate-quality evidence that common etiologies of chronic cough in children are different from those in adults and are dependent on age and setting. As there are few data relating OSA and chronic cough in children, the panel suggested that these children should be managed in accordance with pediatric sleep guidelines.

Management of Children With Chronic Wet Cough and Protracted Bacterial Bronchitis: CHEST Guideline and Expert Panel Report

BACKGROUND

Wet or productive cough is common in children with chronic cough. We formulated recommendations based on systematic reviews related to the management of chronic wet cough in children (aged ≤ 14 years) based on two key questions: (1) how effective are antibiotics in improving the resolution of cough? If so, what antibiotic should be used and for how long? and (2) when should children be referred for further investigations?

METHODS

We used the CHEST expert cough panel's protocol for systematic reviews and the American College of Chest Physicians (CHEST) methodologic guidelines and GRADE framework (the Grading of Recommendations Assessment, Development and Evaluation). Data from the systematic reviews in conjunction with patients' values and preferences and the clinical context were used to form recommendations. Delphi methodology was used to obtain consensus for the recommendations/suggestions made.

RESULTS

Combining data from the systematic reviews, we found high-quality evidence in children aged ≤ 14 years with chronic (> 4 weeks' duration) wet/productive cough that using appropriate antibiotics improves cough resolution, and further investigations (eg, flexible bronchoscopy, chest CT scans, immunity tests) should be undertaken when specific cough pointers (eg, digital clubbing) are present. When the wet cough does not improve following 4 weeks of antibiotic treatment, there is moderate-quality evidence that further investigations should be considered to look for an underlying disease. New recommendations include the recognition of the clinical diagnostic entity of protracted bacterial bronchitis.

CONCLUSIONS

Compared with the 2006 Cough Guidelines, there is now high-quality evidence for some, but not all, aspects of the management of chronic wet cough in specialist settings. However, further studies (particularly in primary health) are required.

Use of Management Pathways or Algorithms in Children With Chronic Cough: CHEST Guideline and Expert Panel Report

BACKGROUND

Using management algorithms or pathways potentially improves clinical outcomes. We undertook systematic reviews to examine various aspects in the generic approach (use of cough algorithms and tests) to the management of chronic cough in children (aged ≤ 14 years) based on key questions (KQs) using the Population, Intervention, Comparison, Outcome format.

METHODS

We used the CHEST Expert Cough Panel's protocol for the systematic reviews and the American College of Chest Physicians (CHEST) methodological guidelines and Grading of Recommendations Assessment, Development and Evaluation framework. Data from the systematic reviews in conjunction with patients' values and preferences and the clinical context were used to form recommendations. Delphi methodology was used to obtain the final grading.

RESULTS

Combining data from systematic reviews addressing five KQs, we found high-quality evidence that a systematic approach to the management of chronic cough improves clinical outcomes. Although there was evidence from several pathways, the highest evidence was from the use of the CHEST approach. However, there was no or little evidence to address some of the KQs posed.

CONCLUSIONS

Compared with the 2006 Cough Guidelines, there is now high-quality evidence that in children aged ≤ 14 years with chronic cough (> 4 weeks' duration), the use of cough management protocols (or algorithms) improves clinical outcomes, and cough management or testing algorithms should differ depending on the associated characteristics of the cough and clinical history. A chest radiograph and, when age appropriate, spirometry (pre- and post-β₂ agonist) should be undertaken. Other tests should not be routinely performed and undertaken in accordance with the clinical setting and the child's clinical symptoms and signs (eg, tests for tuberculosis when the child has been exposed).

Children With Chronic Wet or Productive Cough--Treatment and Investigations: A Systematic Review

BACKGROUND

Systematic reviews were conducted to examine two related key questions (KQs) in children with chronic (> 4 weeks' duration) wet or productive cough not related to bronchiectasis: KQ1-How effective are antibiotics in improving the resolution of cough? If so, what antibiotic should be used and for how long? KQ2-When should they be referred for further investigations?

METHODS

The systematic reviews were undertaken based on the protocol established by selected members of the CHEST expert cough panel. Two authors screened searches and selected and extracted data. The study included systematic reviews, randomized controlled trials (RCTs), cohort (prospective and retrospective) studies, and cross-sectional studies published in English.

RESULTS

Data were presented in Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowcharts, and the summaries were tabulated. Fifteen studies were included in KQ1 (three systematic reviews, three RCTs, five prospective studies, and four retrospective studies) and 17 in KQ2 (one RCT, 11 prospective studies, and five retrospective studies). Combining data from the RCTs (KQ1), the number needed to treat for benefit was 3 (95% CI, 2.0-4.3) in achieving cough resolution. In general, findings from prospective and retrospective studies were consistent, but there were minor variations.

CONCLUSIONS

There is high-quality evidence that in children aged ≤ 14 years with chronic (> 4 weeks' duration) wet or productive cough, the use of appropriate antibiotics improves cough resolution. There is also high-quality evidence that when specific cough pointers (eg, digital clubbing) are present in children with wet cough, further investigations (eg, flexible bronchoscopy, chest CT scans, immunity tests) should be conducted. When the wet cough does not improve by 4 weeks of antibiotic treatment, there is moderate-quality evidence that children should be referred to a major center for further investigations to determine whether an underlying lung or other disease is present.

Use of Management Pathways or Algorithms in Children With Chronic Cough: Systematic Reviews

BACKGROUND

Use of appropriate cough pathways or algorithms may reduce the morbidity of chronic cough, lead to earlier diagnosis of chronic underlying illness, and reduce unnecessary costs and medications. We undertook three systematic reviews to examine three related key questions (KQ): In children aged ?14 years with chronic cough (> 4 weeks' duration), KQ1, do cough management protocols (or algorithms) improve clinical outcomes? KQ2, should the cough management or testing algorithm differ depending on the duration and/or severity? KQ3, should the cough management or testing algorithm differ depending on the associated characteristics of the cough and clinical history?

METHODS

We used the CHEST expert cough panel's protocol. Two authors screened searches and selected and extracted data. Only systematic reviews, randomized controlled trials (RCTs), and cohort studies published in English were included.

RESULTS

Data were presented in Preferred Reporting Items for Systematic Reviews and Meta-analyses flowcharts and summary tabulated. Nine studies were included in KQ1 (RCT = 1; cohort studies = 7) and eight in KQ3 (RCT = 2; cohort = 6), but none in KQ2.

CONCLUSIONS

There is high-quality evidence that in children aged ?14 years with chronic cough (> 4 weeks' duration), the use of cough management protocols (or algorithms) improves clinical outcomes and cough management or the testing algorithm should differ depending on the associated characteristics of the cough and clinical history. It remains uncertain whether the management or testing algorithm should depend on the duration or severity of chronic cough. Pending new data, chronic cough in children should be defined as > 4 weeks' duration and children should be systematically evaluated with treatment targeted to the underlying cause irrespective of the cough severity.

A cough algorithm for chronic cough in children: a multicenter, randomized controlled study

OBJECTIVES

The goals of this study were to: (1) determine if management according to a standardized clinical management pathway/algorithm (compared with usual treatment) improves clinical outcomes by 6 weeks; and (2) assess the reliability and validity of a standardized clinical management pathway for chronic cough in children.

METHODS

A total of 272 children (mean ± SD age: 4.5 ± 3.7 years) were enrolled in a pragmatic, multicenter, randomized controlled trial in 5 Australian centers. Children were randomly allocated to 1 of 2 arms: (1) early review and use of cough algorithm ("early-arm"); or (2) usual care until review and use of cough algorithm ("delayed-arm"). The primary outcomes were proportion of children whose cough resolved and cough-specific quality of life scores at week 6. Secondary measures included cough duration postrandomization and the algorithm's reliability, validity, and feasibility.

RESULTS

Cough resolution (at week 6) was significantly more likely in the early-arm group compared with the delayed-arm group (absolute risk reduction: 24.7% [95% confidence interval: 13-35]). The difference between cough-specific quality of life scores at week 6 compared with baseline was significantly better in the early-arm group (mean difference between groups: 0.6 [95% confidence interval: 0.29-1.0]). Duration of cough postrandomization was significantly shorter in the early-arm group than in the delayed-arm group (P = .001). The cough algorithm was reliable (κ = 1 in key steps). Feasibility was demonstrated by the algorithm's validity (93%-100%) and efficacy (99.6%). Eighty-five percent of children had etiologies easily diagnosed in primary care.

CONCLUSIONS

Management of children with chronic cough, in accordance with a standardized algorithm, improves clinical outcomes irrespective of when it is implemented. Further testing of this standardized clinical algorithm in different settings is recommended.

Inhaled corticosteroids for subacute and chronic cough in adults

BACKGROUND

Persistent cough is a common clinical problem. Despite thorough investigation and empirical management, a considerable proportion of those people with subacute and chronic cough have unexplained cough, for which treatment options are limited. While current guidelines recommend inhaled corticosteroids (ICS), the research evidence for this intervention is conflicting.

OBJECTIVES

To assess the effects of ICS for subacute and chronic cough in adults.

SEARCH METHODS

We searched the Cochrane Airways Group Register of Trials, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and ClinicalTrials.gov in December 2012 and conducted handsearches.

SELECTION CRITERIA

Two authors independently assessed all potentially relevant trials. All published and unpublished randomised comparisons of ICS versus placebo in adults with subacute or chronic cough were included. Participants with known chronic respiratory disease and asthma were excluded. Studies of cough-variant asthma and eosinophilic bronchitis were eligible.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data pertaining to pre-defined outcomes. The primary outcome was the proportion of participants with clinical cure or significant improvement (over 70% reduction in cough severity measure) at follow up (clinical success). The secondary outcomes included proportion of participants with clinical cure or over 50% reduction in cough severity measure at follow up, mean change in cough severity measures, complications of cough, biomarkers of inflammation and adverse effects. We requested additional data from study authors.

MAIN RESULTS

Eight primary studies, including 570 participants, were included. The overall methodological quality of studies was good. Significant clinical heterogeneity resulting from differences in participants and interventions, as well as variation in outcome measures, limited the validity of comparisons between studies for most outcomes. Data for the primary outcome of clinical cure or significant (> 70%) improvement were available for only three studies, which were too heterogeneous to pool. Similarly, heterogeneity in study characteristics limited the validity of meta-analysis for the secondary outcomes of proportion of participants with clinical cure or over 50% reduction in cough severity measure and clinical cure. One parallel group trial of predominantly chronic cough with 'cough-variant asthma' identified a significant treatment effect and contributed to the majority of statistical heterogeneity for these outcomes. While ICS treatment resulted in a mean decrease in cough score of 0.34 standard deviations (SMD -0.34; 95% CI -0.56 to -0.13; 346 participants), the quality of evidence was low. Heterogeneity also prevented meta-analysis for the outcome of mean change in visual analogue scale score. Meta-analysis was not possible for the outcomes of pulmonary function, complications of cough or biomarkers of inflammation due to insufficient data. There was moderate quality evidence that treatment with ICS did not significantly increase the odds of experiencing an adverse event (OR 1.67; 95% CI 0.92 to 3.04).

AUTHORS' CONCLUSIONS

The studies were highly heterogeneous and results were inconsistent. Heterogeneity in study design needs to be addressed in future research in order to test the efficacy of this intervention. International cough guidelines recommend that a trial of ICS should only be considered in patients after thorough evaluation including chest X-ray and consideration of spirometry and other appropriate investigations.

Cough and exhaled nitric oxide levels: what happens with exercise?

Cough associated with exertion is often used as a surrogate marker of asthma. However, to date there are no studies that have objectively measured cough in association with exercise in children. Our primary aim was to examine whether children with a pre-existing cough have an increase in cough frequency during and post-exercise. We hypothesized that children with any coughing illness will have an increase in cough frequency post-exercise regardless of the presence of exercise-induced broncho-constriction (EIB) or atopy. In addition, we hypothesized that Fractional exhaled nitric oxide (FeNO) levels decreases post-exercise regardless of the presence of EIB or atopy. Children with chronic cough and a control group without cough undertook an exercise challenge, FeNO measurements and a skin prick test, and wore a 24-h voice recorder to objectively measure cough frequency. The association between recorded cough frequency, exercise, atopy, and presence of EIB was tested. We also determined if the change in FeNO post exercise related to atopy or EIB. Of the 50 children recruited (35 with cough, 15 control), 7 had EIB. Children with cough had a significant increase in cough counts (median 7.0, inter-quartile ranges, 0.5, 24.5) compared to controls (2.0, IQR 0, 5.0, p = 0.028) post-exercise. Presence of atopy or EIB did not influence cough frequency. FeNO level was significantly lower post-exercise in both groups but the change was not influenced by atopy or EIB. Cough post-exertion is likely a generic response in children with a current cough. FeNO level decreases post-exercise irrespective of the presence of atopy or EIB. A larger study is necessary confirm or refute our findings.

Parent cough-specific quality of life: development and validation of a short form

BACKGROUND

Cough is a distressing symptom and has a significant effect on many children and their families. Quality-of-life (QOL) measures provide important outcome indicators for clinicians and aid in evaluating the efficacy of interventions.

OBJECTIVE

The aim of this study was to develop and validate a short cough-specific QOL questionnaire for pediatric use.

METHOD

Two sources provided data to establish a shortened version of the Parent Cough-specific Quality of Life (PC-QOL) questionnaire. The first (n=240, 137 boys; median age, 29 months [interquartile range, 14-64 months]) was used for development and cross-validation. Stepwise regression was used to select the reduced set of items, and analyses of reliability, validity, and minimally important differences determined psychometric strength and sensitivity to change. The second independent dataset (n=320, 190 boys; median age, 39.5 months [interquartile range, 16-77 months]) was used as a confirmatory sample.

RESULTS

Forward-step regression identified 8 items that accounted for 95% of the variance in the full-scale PC-QOL questionnaire. This shortened version (PC-QOL-8) was internally consistent (Cronbach α=0.84), had good test-retest reliability (intraclass correlation coefficient=0.66), and demonstrated strong validity (significant correlations with a cough verbal category descriptor score, cough visual analog scale, and subscales of the Short Form-12 General Health scale, the Pediatric Quality of Life Inventory, and the Depression, Anxiety, and Stress Scale). The reduced scale was responsive to change, and a minimally important difference of 0.9 was suggested. These findings were confirmed with the second dataset.

CONCLUSION

The PC-QOL-8 questionnaire is a short, reliable, and valid instrument for assessing the effect of a child's chronic cough. It demonstrated sensitivity to change, and its length and psychometric properties should enhance its potential uptake and routine use in clinical practice and research.