Community-acquired pneumonia in old age: a prospective study of 91 patients admitted from home.

OBJECTIVE to characterize the background, aetiology, clinical course and outcome of community-acquired pneumonia (CAP) in elderly compared with younger patients. DESIGN a 1 year prospective study. SETTING a university hospital in southern Israel. PARTICIPANTS ninety-one patients over 65 years who were hospitalized from their homes with CAP. These patients were compared with a reference group of 54 CAP patients, aged 55-64 years. MEASUREMENTS an intensive work-up (primarily serological) to identify the aetiological causes of CAP. The age groups were compared in terms of variables related to CAP. RESULTS the proportion with pneumococcal infection, the most common aetiology for CAP, increased from 29.6% in the 55-64-year group through 45.6% in the 65-74-year group; up to 57.8% in the 75+ group (P = 0.019). Chlamydia pneumoniae was identified as the aetiological agent in 26.4% of elderly patients. Mortality in patients > or = 75 years was 20% and was significantly higher than in the two younger age groups (P = 0.019). The leucocyte count was significantly higher among the elderly group (P = 0.013) and the serum urea concentration was higher in patients 75 years and older (P = 0.025). The proportion of patients treated with antibiotics before admission decreased with increasing age (P = 0.026). CONCLUSIONS CAP has more serious clinical and abnormal laboratory features in the elderly than younger patients, particularly in those over 75. In independent elderly people, the pneumococcus is the most common causative agent for CAP but other agents, particularly C. pneumoniae, are common. Initial antibiotic treatment for these patients should therefore include a macrolide.