Simon bolivar

P R E DIC T ION RUL E TO IDE NT IF Y LOW-R IS K PATIENTS WITH C OMMUNIT Y-AC QUIR ED PNEUMONIA

A PREDICTION RULE TO IDENTIFY LOW-RISK PATIENTS WITH COMMUNITYACQUIRED PNEUMONIA
MICHAEL J. FINE, M.D., THOMAS E. AUBLE, PH.D., DONALD M. YEALY, M.D., BARBARA H. HANUSA, PH.D., LISA A. WEISSFELD, PH.D., DANIEL E. SINGER, M.D., CHRISTOPHER M. COLEY, M.D., THOMAS J. MARRIE, M.D., AND WISHWA N. KAPOOR,M.D., M.P.H.

ABSTRACT
Background There is considerable variability in
rates of hospitalization of patients with communityacquired pneumonia, in part because of physicians’ uncertainty in assessing the severity of illness at presentation. Methods From our analysis of data on 14,199 adult inpatients with community-acquired pneumonia, we derived a prediction rule that stratifies patients intofive classes with respect to the risk of death within 30 days. The rule was validated with 1991 data on 38,039 inpatients and with data on 2287 inpatients and outpatients in the Pneumonia Patient Outcomes Research Team (PORT) cohort study. The prediction rule assigns points based on age and the presence of coexisting disease, abnormal physical findings (such as a respiratory rate of 30 per minuteor a temperature of 40°C), and abnormal laboratory findings (such as a pH 7.35, a blood urea nitrogen concentration 30 mg per deciliter [11 mmol per liter] or a sodium concentration 130 mmol per liter) at presentation. Results There were no significant differences in mortality in each of the five risk classes among the three cohorts. Mortality ranged from 0.1 to 0.4 percent for class I patients (P0.22), from 0.6 to 0.7 percent for class II (P 0.67), and from 0.9 to 2.8 percent for class III (P 0.12). Among the 1575 patients in the three lowest risk classes in the Pneumonia PORT cohort, there were only seven deaths, of which only four were pneumonia-related. The risk class was significantly associated with the risk of subsequent hospitalization among those treated as outpatients and withthe use of intensive care and the number of days in the hospital among inpatients. Conclusions The prediction rule we describe accurately identifies the patients with communityacquired pneumonia who are at low risk for death and other adverse outcomes. This prediction rule may help physicians make more rational decisions about hospitalization for patients with pneumonia. (N Engl J Med1997;336:243-50.)
©1997, Massachusetts Medical Society.

Hospital admission rates for pneumonia vary markedly from one geographic region to the next,5-7 suggesting that the criteria used for hospitalization are inconsistent. Physicians often rely on their subjective impressions of a patient’s clinical appearance in making the initial decision about the site of care.8 Physicians tend to overestimate the riskof death in patients with pneumonia, and these overestimates are associated with the decision to hospitalize patients at low risk.8 Accurate, objective models of prognosis for community-acquired pneumonia could help physicians assess patients’ risks and improve the decisions about hospitalization.9-19 Previous models have been limited by retrospective design,11,14,15,19 the use of predictorvariables about which information is not readily available to physicians when patients present,9,11,13,15,17-19 and dependence on complex calculations that are difficult to apply in the clinical setting.19 The general applicability of these studies has been limited by the evaluations of performance at single study sites,13,15,16 failure to validate findings in independent patient populations,13,15,19and a nearly exclusive focus on hospitalized patients.10,11,13-15,19 Finally, clinical relevance has been compromised by a reliance on mortality as the sole measure of patient outcomes.10-19 The purposes of this study were to develop a prediction rule for prognosis that would accurately identify patients with community-acquired pneumonia who are at low risk of dying within 30 days of presentation...