Definitions of the level of evidence, strength of recommendation, and net benefit follow the "Major Recommendations."
Clinical and Pathologic Features of Eosinophilic Bronchitis Compared With Classical Asthma and Cough- Variant Asthma
Features |
Eosinophilic Bronchitis |
Classic Asthma |
Cough-Variant Asthma |
Atopic Cough |
Symptoms |
Cough, often associated with upper airway symptoms |
Dyspnea, cough, wheeze |
Isolated cough |
Isolated cough |
Atopy |
Same as general population |
Common |
Common |
Common |
Airway hyperresponsiveness |
Absent |
Present |
Present |
Absent |
Cough reflex hypersensitivity |
Increased |
Normal or increased |
Normal or increased |
Increased |
Response to bronchodilator |
Absent |
Good |
Good |
Absent |
Response to corticosteroids |
Good |
Good* |
Good* |
Good* |
Sputum eosinophilia |
Always |
Usually |
Usually |
Usually |
Bronchial biopsy eosinophilia |
Very common |
Common |
Common |
Common |
Mast cells within airway smooth muscle bundles |
No |
Yes |
Yes |
Unknown |
*When sputum eosinophilia are present.
- In patients with chronic cough who have normal chest radiograph findings, normal spirometry findings, and no evidence of variable airflow obstruction or airway hyperresponsiveness, the diagnosis of nonasthmatic eosinophilic bronchitis should be considered. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In patients with chronic cough with normal chest radiograph findings, normal spirometry findings, and no evidence of variable airflow obstruction or airway hyperresponsiveness, the diagnosis of nonasthmatic eosinophilic bronchitis as the cause of the chronic cough is confirmed by the presence of an airway eosinophilia, either by sputum induction or bronchial wash fluid obtained by bronchoscopy, and an improvement in the cough following corticosteroid therapy. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In patients with chronic cough due to nonasthmatic eosinophilic bronchitis, the possibility of an occupation-related cause needs to be considered. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- For patients with chronic cough due to nonasthmatic eosinophilic bronchitis, the first-line treatment is inhaled corticosteroids (except when a causal allergen or sensitizer is identified [see recommendation 5]). Level of evidence, low; benefit, substantial; grade of recommendation, B
- For patients with chronic cough due to nonasthmatic eosinophilic bronchitis, when a causal allergen or occupational sensitizer is identified, avoidance is the best treatment. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- For patients with chronic cough due to nonasthmatic eosinophilic bronchitis, if symptoms are persistently troublesome and/or the natural history of eosinophilic airway inflammation progresses despite treatment with high-dose inhaled corticosteroids, oral corticosteroids should be given. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
Definitions:
Quality of the Evidence
Good = evidence is based on good randomized controlled trials (RCTs) or meta-analyses
Fair = evidence is based on other controlled trials or RCTs with minor flaws
Low = evidence is based on nonrandomized, case-control, or other observational studies
Expert opinion = evidence is based on the consensus of the carefully selected panel of experts in the topic field. There are no studies that meet the criteria for inclusion in the literature review.
Strength of Recommendations
A = strong recommendation
B = moderate recommendation
C = weak recommendation
D = negative recommendation
I = no recommendation possible (inconclusive)
E/A = strong recommendation based on expert opinion only
E/B = moderate recommendation based on expert opinion only
E/C = weak recommendation based on expert opinion only
E/D = negative recommendation based on expert opinion only
Net Benefit
Substantial = There is evidence of benefit that clearly exceeds the minimum clinically significant benefit and evidence of little harm
Intermediate = Clear evidence of benefit but with some evidence of harms, with a net benefit between that defined for "substantial" and "small/weak"
Small/weak = There is evidence of a benefit that may not clearly exceed the minimum clinically significant benefit, or there is evidence of harms that substantially reduce (but do not eliminate) the benefit such that it may not clearly exceed the minimum clinically significant benefit
None = Evidence shows that either there is no benefit or the benefits equal the harms
Conflicting = Evidence is inconsistent with regard to benefits and/or harms such that the net benefit is uncertain
Negative = Expected harms exceed the expected benefits to the population
Table: Relationship of Strength of the Recommendations Scale to Quality of Evidence and Net Benefits
|
Net Benefit |
Quality of Evidence |
Substantial |
Intermediate |
Small/Weak |
None |
Conflicting |
Negative |
Good |
A |
A |
B |
D |
I |
D |
Fair |
A |
B |
C |
D |
I |
D |
Low |
B |
B |
C |
I |
I |
D |
Expert Opinion |
E/A |
E/B |
E/C |
I |
I |
E/D |