Applying a prediction rule to identify low-risk patients with community-acquired pneumonia

Study objectives: To study the validity of a recently developed community-a cquired pneumonia (CAP) severity prediction rule in estimating mortality, t o determine its utility in decision making regarding hospitalization, and t o assess factors influencing this decision. Design: Retrospective chart review. Setting: Two sites of the University Health Network, the Toronto General an d Toronto Western Hospitals, tertiary-care teaching institutions with a siz able primary-care and secondary-care source of referrals, and a total of 90 0 beds. Patients: Consecutive patients with CAP admitted between February and June 1996. Measurements and results: A single trained medical records extractor assemb led data to compare our population to that used in developing the CAP predi ction rule, in terms of mortality and to assess reasons for hospitalization . Two hundred fifty-five eligible patients were admitted, and 244 charts (9 6%) were available. Our patients tended to be older, with nearly four times as many residents of chronic care institutions (39% compared with 10%), an d had a higher risk class distribution than the published cohort. Risk clas s-specific mortality was similar in four of five classes. Of the 71 patient s in the low-risk classes, 67 had additional reasons for admission; 18 of w hich were psychosocial (homelessness, substance abuse, or inadequate home s upports). Conclusions: The CAP severity prediction rule estimates mortality well. Adm ission of low-risk patients was linked to psychosocial and other medical re asons not captured by this rule. The rule can be very useful in assessing t he need for hospitalization; however, there remains a significant percentag e of patients with a low severity score who may require hospitalization for psychosocial and economic considerations.