Community-acquired pneumonia: a clinical prediction rule can help predict 30 day mortality.

Clinical bottom line (level 1a)

  1. One in twenty patients with community-acquired pneumonia will be dead at 30 days.
  2. A clinical prediction rule can be used to rank patients for risk of dying.
  3. Patients in class I - III are unlikely to die. One in eleven patients in class IV die, and one in four patients in class V die.
Fine et al: New England Journal of Medicine 1997; 336: 243-250
Expires March 2003

The study

Outcome study with objective outcomes, adjusted for confounding factors, validated in an independent set of patients.

Setting: 78 acute hospitals in 23 states, USA

14199 patients (aged 17% <50 years old, 51% female) inpatients with a principle diagnosis of community-acquired pneumonia (according to the International Classification of Diseases, 9th Revision, Clinical Modification)

Excluded if
  • <18 years old
  • history of AIDS or a positive titre of antibodies to HIV
  • hospitalised previously within seven days before the current admission or transferred from another acute care hospital




    • Mortality rates were compared with Chi-squared and area under the curve.

    100% followed for 30 days
    Outcomes studied:
  • overall mortality
  • mortality in risk class V
  • mortality of risk class IV
  • mortality of risk class III
  • mortality of risk class II
  • mortality of risk class I

    • A clinical prediction rule was created and validated in retrospective cohort of 38039 patients, and a prospective outcome study (PORT) of 2287 patients
    • Clinical prediction rule: assign patients to class I if patients are aged < 50 and
      • none of the conditions listed below
      • none of the physical findings listed below
      otherwise use the following scoring system - sum the components
    • age (years) for men; age (years) - 10 for women
    • nursing home resident: +10
    • co-existing disease
      • neoplastic disease + 30
      • liver disease +20
      • congestive heart failure +10
      • cerebrovascular disease +10
      • renal disease +10
    • physical examination findings
      • altered mental status +20
      • respiratory rate 30/minute or more +20
      • systolic blood pressure < 90 mmHg +20
      • temperature 35 C or lower, 40 C or more +15
      • pulse 125 beats/min or more +10
    • Laboratory and radiographic findings
      • arterial pH < 7.35 +30
      • urea 11 mmol/l or more +20
      • sodium <130 mmol/l +20
      • glucose 14 mmol/l or more +10
      • haematocrit < 30% +10
      • partial pressure of arterial oxygen < 60 mmHg +10
      • pleural effusion +10
    • score
      • class II: 70 or lower
      • class III: 71 to 90
      • class IV: 91 to 130
      • class V: 131 or higher

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)    		 NNF
    (95% CI)
    overall mortality 30 days 113/2287 4.9%
    (4.1% to 5.8%)    		 20
    (17 to 25)
    mortality in risk class V 30 days 61/226 27%
    (21% to 33%)    		 4
    (3 to 5)
    mortality of risk class IV 30 days 45/486 9.3%
    (6.7% to 12%)    		 11
    (8 to 15)
    mortality of risk class III 30 days 3/326 0.92%
    (0.0% to 2.0%)    		 110
    (51 to infinity)
    mortality of risk class II 30 days 3/477 0.63%
    (0.0% to 1.3%)    		 160
    (75 to infinity)
    mortality of risk class I 30 days 1/772 0.13%
    (0.0% to 0.38%)    		 770
    (260 to infinity)

    Comments

    1. The prediction rule was validated in two other sets of patients, each of which confirmed the use of risk classes in predicting mortality.

    Citation

    1. Fine MJ, Auble TE, Yealy DM, et al: A prediction rule to identify low-risk patients with community-acquired pneumonia. New England Journal of Medicine 1997; 336: 243-250
    Search Terms: community-acquired pneumonia prognosis in Medline
    Contributor: Clare Wotton and Chris Ball, November 1999
    Reviewer:

    Clinical Question.
    Patient community-acquired pneumonia
    Intervention or Exposure prediction rule
    Comparison
    Outcome mortality