Point-of-Care Guides

Identifying Outpatients with Acute Cough at Very Low Risk of Pneumonia

 

Am Fam Physician. 2019 Aug 15;100(4):246-247.

Author disclosure: No relevant financial affiliations.

Clinical Question

In patients with acute cough, is it possible to identify a subset with a very low likelihood of having community-acquired pneumonia (CAP)?

Evidence Summary

Acute cough is one of the most common reasons for patients to see a family physician and receive antibiotics.1 Although there is good evidence that most of these infections are viral and do not benefit from antibiotics,2 physicians may be concerned that they will miss a CAP diagnosis. It would therefore be helpful to identify a subset of patients with a very low risk of CAP, reducing not only the number of patients treated unnecessarily with antibiotics, but also the number who undergo chest radiography.

A large European study (GRACE) prospectively recorded signs and symptoms in 2,820 primary care patients with acute cough, all of whom received chest radiography. The study found that only 5% had CAP.3 Two older U.S. primary care studies also found a 3% to 5% prevalence of CAP among patients with acute cough.4,5

The signs and symptoms that best predicted pneumonia in the GRACE study were used to create a clinical decision rule that can be used to determine the likelihood of CAP (Table 13). The two older U.S. studies found a generally similar set of signs and symptoms to be predictive of CAP.4,5 Of note, the GRACE rule includes a C-reactive protein measurement, which is available as a point-of-care test in countries outside of the United States but requires a moderate-complexity laboratory in the United States. Another limitation of the GRACE rule is that most patients are classified in the intermediate-risk group, with only 20% falling into the low-risk group. Although helpful for identifying patients at high risk of CAP, all of these clinical prediction rules are less helpful for identifying patients at low risk.

 Enlarge     Print

TABLE 1.

Accuracy of the European GRACE Clinical Decision Rule for the Diagnosis of CAP

Clinical variable

Points


Absence of runny nose

1

Crackles on lung examination

1

Diminished vesicular breathing

1

Breathlessness (shortness of breath)

1

Pulse more than 100 beats per minute

1

Fever higher than 100.5°F (38°C)

1

C-reactive protein level more than

1

30 mg per L (285.7 nmol per L)

Total

_____

Risk group (total points)

Patients with CAP/total (%)


Low (0)

4/572 (0.7%)

Moderate (1 or 2)

73/1,902 (3.8%)

High (3 or more)

63/346 (18.2%)


CAP = community-acquired pneumonia.

Information from reference 3.

TABLE 1.

Accuracy of the European GRACE Clinical Decision Rule for the Diagnosis of CAP

Clinical variable

Points


Absence of runny nose

1

Crackles on lung examination

1

Diminished vesicular breathing

1

Breathlessness (shortness of breath)

1

Pulse more than 100 beats per minute

1

Fever higher than 100.5°F (38°C)

1

C-reactive protein level more than

1

30 mg per L (285.7 nmol per L)

Total

_____

Risk group (total points)

Patients with CAP/total (%)


Low (0)

4/572 (0.7%)

Moderate (1 or 2)

73/1,902 (3.8%)

High (3 or more)

63/346 (18.2%)


CAP = community-acquired pneumonia.

Information from reference 3.

Physicians often do not use clinical decision rules to predict the risk of CAP and instead use their overall clinical impression, also called “clinical gestalt.” A recent systematic review identified 10 studies that reported the accuracy of clinical gestalt for the diagnosis of CAP (Table 26,7), with overall estimates of the positive and negative likelihood ratios of 7.70 and 0.54, respectively.6 Given a 5% baseline risk of CAP, those whose physicians have an overall clinical impression favoring pneumonia would have a 29% risk of CAP, and those whose physicians have a negative overall clinical impression would have a 2.8% risk of CAP.

 Enlarge     Print

TABLE 2.

Accuracy of the Physician's Overall Clinical Impression and the Pneumonia Rule-Out Criteria Given a 5% Overall Likelihood of CAP

SignPatients with CAP (%)

Overall clinical impression is positive for CAP

29%

Overall clinical impression is negative for CAP

2.8%

Pneumonia rule-out criteria met (i.e., normal vital signs* and lung examination)

0.5%


CAP = community-acquired pneumonia.

*—Temperature lower than 100.5°F (38°C), respiratory rate less than 20 breaths per minute, and heart rate lower than 100 beats per minute.

Information from references 6 and 7.

TABLE 2.

Accuracy of the Physician's Overall Clinical Impression and the Pneumonia Rule-Out Criteria Given a 5% Overall Likelihood of CAP

SignPatients with CAP (%)

Overall clinical impression is positive for CAP

29%

Overall clinical impression is negative for CAP

2.8%

Pneumonia rule-out criteria met (i.e., normal vital signs* and lung examination)

0.5%


CAP = community-acquired pneumonia.

*—Temperature lower than 100.5°F (38°C), respiratory rate less than 20 breaths per minute, and heart rate lower than 100 beats per minute.

Information from references 6 and 7.

Another recent study used clinical vignettes that systematically

Address correspondence to Mark H. Ebell, MD, MS, at ebell@uga.edu. Reprints are not available from the author.

Author disclosure: No relevant financial affiliations.

References

show all references

1. Fleming-Dutra KE, Hersh AL, Shapiro DJ, et al. Prevalence of inappropriate antibiotic prescriptions among US ambulatory care visits, 2010–2011. JAMA. 2016;315(17):1864–1873....

2. Harris AM, Hicks LA, Qaseem A. Appropriate antibiotic use for acute respiratory tract infection in adults: advice for high-value care from the American College of Physicians and the Centers for Disease Control and Prevention. Ann Intern Med. 2016;164(6):425–434.

3. van Vugt SF, Broekhuizen BD, Lammens C, et al. Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: diagnostic study. BMJ. 2013;346:f2450.

4. Diehr P, Wood RW, Bushyhead J, et al. Prediction of pneumonia in out-patients with acute cough. J Chronic Dis. 1984;37(3):215–225.

5. Heckerling PS, Tape TG, Wigton RS, et al. Clinical prediction rule for pulmonary infiltrates. Ann Intern Med. 1990;113(9):664–670.

6. Dale AP, Marchello C, Ebell MH. Clinical gestalt to diagnose pneumonia, sinusitis, and pharyngitis: a meta-analysis. Br J Gen Pract. 2019;69(684):e444–e453.

7. Marchello CS, Ebell MH, Dale AP, et al. Signs and symptoms that rule out community-acquired pneumonia in outpatient adults. J Am Board Fam Med. 2019;32(2):234–247.

8. Ebell MH, Locatelli I, Mueller Y, et al. Diagnosis and treatment of community-acquired pneumonia in patients with acute cough. Br J Gen Pract. 2018;68(676):e765–e774.

This guide is one in a series that offers evidence-based tools to assist family physicians in improving their decision-making at the point of care.

This series is coordinated by Mark H. Ebell, MD, MS, Deputy Editor for Evidence-Based Medicine.

A collection of Point-of-Care Guides published in AFP is available at https://www.aafp.org/afp/poc.

 

 

Copyright © 2019 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

Want to use this article elsewhere? Get Permissions

CME Quiz

More in AFP

More in Pubmed

MOST RECENT ISSUE


Sep 15, 2019

Access the latest issue of American Family Physician

Read the Issue


Email Alerts

Don't miss a single issue. Sign up for the free AFP email table of contents.

Sign Up Now

Navigate this Article