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Am Fam Physician. 2002;66(1):135-138

Questions Addressed

  • What are the effects of antibiotics in outpatient settings?

  • What are the effects of treatments in people admitted to the hospital?

  • What are the effects of treatments in people in intensive care?

  • What are the effects of guidelines?

  • What are the effects of preventive interventions?

Likely to be beneficial
Prompt administration of antibiotics in people severely ill with community-acquired pneumonia
Unknown effectiveness
Bottle blowing
Specific combinations of antibiotics in intensive care settings
Guidelines for treating pneumonia (for clinical outcomes)
Unlikely to be beneficial
New antibiotics versus older antibiotics in outpatient settings, unless microbes are resistant to older drugs
New antibiotics versus older antibiotics in the hospital, unless microbes are resistant to older drugs
Intravenous antibiotics versus oral antibiotics in immunocompetent people in the hospital without a life-threatening illness
Pneumococcal vaccine in immunocompetent adults
Likely to be beneficial
Influenza vaccine in elderly people
Unknown effectiveness
Pneumococcal vaccine in chronically ill, immunosuppressed, or elderly people
Related topics covered in Clinical Evidence
Antivirals for influenza
To be covered in future issues of Clinical Evidence
Other antiviral treatments
DefinitionCommunity-acquired pneumonia is pneumonia contracted in the community rather than in the hospital.
Incidence/PrevalenceIn the northern hemisphere, community-acquired pneumonia affects about 12 per 1,000 people a year, particularly during winter and at the extremes of age (incidence: <1 year of age, 30 to 50 per 1,000 a year; 15 to 45 years of age, 1 to 5 per 1,000 a year; 60 to 70 years of age, 10 to 20 per 1,000 a year; 71 to 85 years of age, 50 per 1,000 a year).16
Etiology/Risk FactorsMore than 100 microorganisms have been implicated in community-acquired pneumonia, but most cases are caused by Streptococcus pneumoniae.47 Smoking is probably an important risk factor.8
PrognosisSeverity varies from mild to life-threatening illness within days of the onset of symptoms. One systematic review (search date 1995, 33,148 people) of prognosis studies for community-acquired pneumonia found overall mortality to be 13.7 percent, ranging from 5.1 percent for ambulant people to 36.5 percent for people requiring intensive care.9 The following prognostic factors were significantly associated with mortality: male sex (overall risk [OR]: 1.3; 95 percent confidence interval [CI]: 1.2 to 1.4); pleuritic chest pain (OR: 0.5; 95 percent CI: 0.3 to 0.8 [i.e., lower mortality]); hypothermia (OR: 5; 95 percent CI: 2.4 to 10.4); systolic hypotension (OR: 4.8; 95 percent CI: 2.8 to 8.3); tachypnea (OR: 2.9; 95 percent CI: 1.7 to 4.9); diabetes mellitus (OR: 1.3; 95 percent CI: 1.1 to 1.5); neoplasticdisease (OR: 2.8; 95 percent CI: 2.4 to 3.1); neurologic disease (OR: 4.6; 95 percent CI: 2.3 to 8.9); bacteremia (OR: 2.8; 95 percent CI: 2.3 to 3.6); leukopenia (OR: 2.5; 95 percent CI: 1.6 to 3.7); and multilobar radiographic pulmonary infiltrates (OR: 3.1; 95 percent CI: 1.9 to 5.1).
Clinical AimsTreatment: to cure infection; to prevent death; to alleviate symptoms; to enable return to normal activities; and to prevent recurrence, while minimizing adverse effects of treatments. Prevention: to prevent onset of pneumonia.
Clinical OutcomesClinical cure (defined as return to premorbid health status); relief of symptoms; admission to hospital; complications (empyema, endocarditis, lung abscess); death; adverse effects of antibiotics.



One systematic review comparing different oral antibiotics in outpatient settings has found cure or improvement in more than 90 percent of people.


Randomized controlled trials (RCTs) found no significant difference between new and older antibiotics in cure of people with community-acquired pneumonia admitted to the hospital. However, most trials were small and were designed to show equivalence between treatments rather than superiority of one over another.


Two RCTs found that, in immunocompetent people admitted to the hospital who were not suffering from life-threatening illness, intravenous antibiotics were no more effective than oral antibiotics and increased the length of hospital stay.


One unblinded RCT found limited evidence that bottle blowing physiotherapy (blowing bubbles via a narrow tube inserted in water) plus early mobilization plus encouragement to regularly sit up and take deep breaths versus early mobilization alone significantly reduced hospital stay.


We found no RCTs comparing one combination of antibiotics versus another in intensive care units.


Two retrospective studies found that prompt administration of antibiotics significantly improved survival.


One systematic review comparing a guideline incorporating early switch from intravenous to oral antibiotics and/or early discharge strategies versus usual care has found no significant difference in clinical outcomes.



One RCT found that influenza vaccine versus placebo significantly reduced the incidence of influenza in people 60 years and older. Another RCT found that intranasal live vaccine plus parenteral vaccine versus parenteral vaccine alone significantly reduced the incidence of influenza A in elderly people. Two RCTs found that the offer of vaccination of health care workers versus no offer of vaccination significantly reduced mortality in elderly people in long-term care hospitals.


One systematic review has found that pneumococcal vaccination versus no vaccination significantly reduces pneumococcal pneumonia in immunocompetent people, but found no significant difference between pneumococcal vaccination versus no vaccination in elderly people or people likely to have an impaired immune system.

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