Combining information from prognostic scoring tools for CAP: an American view on how to get the best of all worlds

Many studies of the epidemiology of patients with community-acquired pneumonia (CAP) have demonstrated the importance of assessing severity of illness and stratifying patients on the basis of their risk of mortality 1–3. Optimal management of this illness requires prompt recognition of seriously ill patients to avoid mistakes such as the failure to use a hospital or intensive care unit (ICU) for patients who could benefit from care and observation in such settings. The major impact on the cost of CAP care is determined by whether or not a patient is admitted to the hospital. In the USA, 90% of the total cost of care for this disease 4. Prognostic scoring systems for CAP have been developed to address these issues. The two prominent tools for this purpose are the Pneumonia Severity Index (PSI), developed in the USA, and the British Thoracic Society rule, which has recently been modified to the CURB-65 rule (referring to its assessment of: Confusion, elevated blood Urea nitrogen, elevated Respiratory rate, low systolic or diastolic Blood pressure, and age >65 yrs) 1, 3. Although each of the two approaches has been proposed as a tool to guide the site of care decision, neither is ideal by itself, and both can be regarded only as providing decision support information that must be supplemented by clinical assessment and judgment. In fact, the two scoring approaches should be viewed as being complementary, as each has different strengths and weaknesses. The PSI seems to have been developed, and best validated, as a way to identify low mortality risk patients, but the scoring system can occasionally underestimate severity of illness, especially in young patients without comorbid illness 2 …