Risks and outcomes in community acquired pneumonia.

Risks and probable outcomes in patients with community acquired pneumonia have always been assessed intuitively by clinicians, but are now being intensively and formally studied. Several risk scoring systems have been developed to assign patients to different risk categories, with respect to important outcomes such as mortality or intensive care unit admission. Predictive factors include demographic characteristics such as age and sex, comorbidities such as neoplastic disease or congestive heart failure, abnormalities on physical examination and abnormal laboratory findings. Prospective use of one such prediction rule found a mortality rate of 0.5% in the lowest risk category, rising to 27.1% in the highest risk group. Formal assessment of risk can assist the clinician in deciding whether to treat a patient at home or in hospital, and can be an important step in developing clinical practice guidelines.