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Research Findings for Clinicians
Overview
A new clinical prediction model can help clinicians determine
the most appropriate care for newly diagnosed cases of
community-acquired pneumonia (CAP). The model
recently was announced by a team of researchers supported through
a grant from the Federal Agency for Health Care Policy and
Research (AHCPR).
The model stratifies patients into risk categories based on
their medical history, physical examination findings, and a
limited set of laboratory and radiographic results. This is a
major breakthrough, since the factors used to predict risk are
clearly defined and can be readily assessed at the time of
patient presentation.
The model also predicts other important medical outcomes, such
as length of hospitalization, admission to an intensive care unit
for respiratory failure or hemodynamic compromise, and time to
usual activities.
About 600,000 of the 4 million Americans who develop CAP each
year are hospitalized. Because of a lack of evidence-based
admission criteria and the tendency to overestimate the risk of
death, many low-risk patients who could just as safely be treated
as outpatients are instead admitted for more costly inpatient
care.
The investigators made projections from a prospective cohort
study of 2,287 CAP patients in Pittsburgh, Boston, and Halifax,
Nova Scotia. They suggest that if the model had been used, 26-31
percent of the patients who were hospitalized for care could have
been treated safely as outpatients, and an additional 13-19
percent could have been hospitalized only briefly for
observation. The investigators validated the model for accuracy
and general applicability with data on over 50,000 CAP patients
in 275 U.S. and Canadian hospitals.
During the first step of patient assessment, the patient's
risk level is evaluated using factors such as age, presence of
other illnesses, and abnormal physical examination findings. For
patients not defined as low risk in the first step, results of
laboratory tests are used to further ascertain risk of death or
other adverse outcomes.
The researchers caution that clinicians may need to consider
factors other than risk before deciding that a patient should
have home therapy. These include patient preferences, ability to
maintain oral intake, history of substance abuse, cognitive
impairment, and ability to independently carry out activities of
daily living. Nevertheless, preliminary evidence from this study
shows that applying the prediction model in clinical practice
could reduce the need for hospitalization of CAP patients without
jeopardizing their health and quality of care. A firm
recommendation for its clinical use will depend on future
prospective trials to confirm its effectiveness and safety.
Investigators also compared medical outcomes for ambulatory
and hospitalized low-risk CAP patients; assessed physician and
patient decision-making processes for initial site of care and
length of hospital stay; documented resource use and costs of
treatment; and identified preventive health care issues. Some of
their conclusions follow:
- More expensive antimicrobial therapy and longer hospital
stays may not lead to better outcomes than can be
obtained with less costly antimicrobial therapy and
shorter stays.
- Many patients hospitalized for CAP—up to one-fifth
of them—remain hospitalized beyond the time they
reach clinical stability.
- Most low-risk CAP patients prefer home care, but
physicians generally do not ask them their preference.
- The two areas most likely to result in major cost savings
for CAP are reducing admissions of low-risk patients and
decreasing length of hospital stay. Researchers also
recommend studying prescribing practices for
antimicrobial drugs for ways to improve their
cost-effectiveness for CAP.
About the Study
The study, reported in the January 23, 1997 issue of The
New England Journal of Medicine, was conducted as part of the
Pneumonia Patient Outcomes Research Team (PORT), a 5-year,
multi-center AHCPR-supported project directed by Wishwa N.
Kapoor, M.D., M.P.H., of the University of Pittsburgh School of
Medicine. PORTs are a series of studies on the quality,
effectiveness, and cost-effectiveness of current therapies for
treating some of the most common and costly medical conditions in
the United States.
The lead author of the January 23 article in New England
Journal of Medicine, Michael J. Fine, M.D., M.Sc., was
supported as a Robert Wood Johnson Foundation Generalist
Physician Faculty Scholar. The PORT team also included other
investigators with the University of Pittsburgh School of
Medicine and Graduate School of Public Health, Pittsburgh
Research Institute, Harvard Medical School, and Dalhousie
University.
Pneumonia Study Publications
A partial list of studies from the Pneumonia PORT, shown in
reverse chronological order, follows.
- Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to
identify low-risk patients with community-acquired
pneumonia. The New England Journal of Medicine 1997 (January 23); 336:243-250.
- Fine MJ, Hough LJ, Medsger AR, et al. The hospital
admission decision for patients with community-acquired
pneumonia: Results from the Pneumonia PORT. Archives
of Internal Medicine 1997 (January 13); 157:36-44.
- Fine MJ, Medsger AR, Stone RA, et al. The hospital
discharge decision for patients with community-acquired
pneumonia: Results from the Pneumonia PORT. Archives
of Internal Medicine 1997 (January 13); 157:47-56.
Coley
CM, Li YH, Medsger AR, et al. Preferences for home versus
hospital care among low-risk patients with
community-acquired pneumonia. Archives of Internal
Medicine 1996 (July 22); 156:1565-1571.
- Minogue MF, Hough LJ, Fine MJ, et al. Patients
hospitalized after initial ambulatory therapy for
community-acquired pneumonia. Journal of General
Internal Medicine 1996 (April); 11(supplement 1):52A.
- Fine MJ, Smith MA, Carson CA, et al. Prognosis and
outcomes of patients with community-acquired pneumonia: A
meta-analysis. The Journal of the American
Medical Association 1996 (January 10); 275:2.
For the full bibliography of publications related to this
study see Assessment of the Variation and Outcomes of
Pneumonia: Pneumonia Patient Outcomes Research Team Final Report.
The report is available from the National Technical Information
Service (NTIS), Springfield, VA 22161, (703) 487-4650. Ask for
accession number PB97-117808. It also is available from the AHCPR
Clearinghouse (AHCPR Publication No. 97-N009).
Printed copies of Pneumonia: New Prediction Model Proves
Promising (AHCPR Publication No. 97-R031), as well as a fact sheet
for consumers, Pneumonia:
More Patients May Be Treated At Home (AHCPR Publication No.
97-R030), are available by calling the AHCPR Publications
Clearinghouse at (800) 358-9295. From outside the United States,
call (703) 437-2078.
The prediction model consists of an algorithm,
a scoring system, and a stratification table of the risk score.
Select graphic file (26
KB) or text file for the model's
algorithm.
Scoring System for Prediction Model
Patient characteristic | Points assigned(1) |
Demographic factors |
Age: |
o Males: | Age (in years) |
o Females: | Age (in years) -10 |
Nursing home resident: | +10 |
Comorbid illnesses |
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 degrees C
or 40 degrees C or more: | +15 |
Pulse 125/minute or more: | +10 |
Laboratory findings |
pH <7.35: | +30 |
BUN >10.7 mmol/L: | +20 |
Sodium <130 mEq/L: | +20 |
Glucose >13.9 mmol/L: | +10 |
Hematocrit <30 percent: | +10 |
PO2 <60 mmHg (2): | +10 |
Pleural effusion: | +10 |
(1) A risk score (total point score) for a given patient is
obtained
by summing the patient age in years (age minus 10
for females) and
the points for each applicable patient
characteristic.
(2) Oxygen saturation <90 percent also was considered
abnormal.
Stratification of Risk Score for Prediction Model
Risk | Risk Class | Based on |
Low | I | Algorithm |
Low | II | 70 or fewer total points |
Low | III | 71-90 total points |
Moderate | IV | 91-130 total points |
High | V | > 130 total points |
This prediction model for prognosis in patients with
community-acquired pneumonia may be used to help guide the
initial decision on site of care. However, its use may not be
appropriate for all patients with this illness and therefore
should be applied in conjunction with physician judgment.
AHCPR Publication No. 97-R031
Current as of January 1997