Definitions for the level of evidence, strength of recommendation, and net benefit follow the "Major Recommendations."
1. In patients with cough, the starting point is the medical history and physical examination. Although the timing and characteristics of the cough are of little diagnostic value, the medical history is important to determine whether the patient is receiving an angiotensin-converting enzyme (ACE) inhibitor, is a smoker, or has evidence of a serious life-threatening or systemic disease. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
2. In patients with an acute cough, first determine whether the acute cough is a reflection of a serious illness such as pneumonia or pulmonary embolism, or, as is usually the case, a manifestation of a nonlife-threatening disease such as a respiratory tract infection (e.g., common cold or lower respiratory tract infection), an exacerbation of a preexisting condition (e.g., chronic obstructive pulmonary disease (COPD), upper airway cough syndrome (UACS), asthma, or bronchiectasis), or an environmental or occupational exposure to some noxious or irritating agent (e.g., allergic or irritant-induced rhinitis). Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
3. In patients with a subacute cough, first determine whether it is a postinfectious cough or not. If it is postinfectious, determine whether it is a result of UACS, transient bronchial hyperresponsiveness, asthma, pertussis, or an acute exacerbation of chronic bronchitis. If it is noninfectious, manage the cough the same way as chronic cough (see clinical algorithm entitled "Subacute cough algorithm for the management of patients >15 years of age with cough lasting 3 to 8 weeks", in the original guideline document). Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
4a. In patients with chronic cough, systematically direct empiric treatment at the most common causes of cough (ie, UACS, asthma, nonasthmatic eosinophilic bronchitis (NAEB), and gastroesophageal reflux disease [GERD]). Level of evidence, low; benefit, substantial; grade of recommendation, B
4b. In patients with chronic cough, therapy should be given in sequential and additive steps because more than one cause of cough may be present. Level of evidence, low; benefit, substantial; grade of recommendation, B
5. Patients with a chronic cough who smoke should be counseled and assisted with smoking cessation. Level of evidence, low; benefit, substantial; grade of recommendation, B
6. In a patient with cough who is receiving an ACE inhibitor, therapy with the drug should be stopped and the drug should be replaced. Level of evidence, low; benefit, substantial; grade of recommendation, B
7. In patients with chronic cough, initial empiric treatment should begin with an oral first-generation antihistamine/decongestant (A/D). Level of evidence, low; benefit, substantial; grade of recommendation, B
8a. In patients whose chronic cough persists after treatment for UACS, the possibility that asthma is the cause of cough should be worked up next. The medical history is sometimes suggestive, but is not reliable in either ruling in or ruling out asthma. Therefore, ideally, bronchoprovocation challenge (BPC), if spirometry does not indicate reversible airflow obstruction, should be performed in the evaluation for asthma as a cause of cough. In the absence of the availability of BPC, an empiric trial of antiasthma therapy should be administered. Level of evidence, low; benefit, substantial; grade of recommendation, B
8b. In patients with chronic cough, in whom the diagnoses of UACS and asthma have been eliminated or treated without the elimination of cough; NAEB should be considered next with a properly performed induced sputum test for eosinophils. If a properly performed induced sputum test to determine whether eosinophilic bronchitis is present cannot be performed, an empiric trial of corticosteroids should be the next step. Level of evidence, low; benefit, substantial; grade of recommendation, B
9. In the majority of patients with suspected cough due to asthma, ideally, before starting an oral corticosteroid regimen, a BPC should be performed and, if the result is positive, some combination therapy of inhaled corticosteroids (ICSs), inhaled beta-agonists, or oral leukotriene inhibitors should be administered. A limited trial of oral corticosteroids, however, should be administered in some patients who are suspected of having asthma-induced cough before eliminating the diagnosis from further consideration. Level of evidence, low; benefit, substantial; grade of recommendation, B
10. In patients whose cough responds only partially or not at all to interventions for UACS and asthma or NAEB, treatment for GERD should be instituted next. Level of evidence, low; benefit, substantial; grade of recommendation, B
11. In patients with cough whose condition remains undiagnosed after all of the above has been done, referral to a cough specialist is indicated. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
For more complete diagnosis and treatment recommendations (as indicated in the algorithm of the original guideline document), please refer to the following National Guideline Clearinghouse (NGC) summaries of the American College of Chest Physician's guidelines:
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 |
