Pneumonia is the fifth leading cause of death in the United States in patients older than 65 years. It also is one of the more common reasons for hospitalizing patients in this age group. Multiple studies have shown that timely administration of antibiotics to patients admitted for treatment of pneumonia improves survival. Recent published guidelines from two organizations have recommended that patients admitted with community-acquired pneumonia (CAP) receive the first dose of antibiotics within eight hours of admission. One of these studies found that the relationship between early antibiotic administration and survival was stronger when patients who had received prehospitalization antibiotics were excluded from the analysis. Houck and colleagues assessed the relationship between the timing of the first antibiotic dose and mortality, length of stay, and readmission rates in patients older than 65 years who were hospitalized for CAP. In particular, they evaluated only those patients who had not received any antibiotic treatment before admission to the hospital.

The study was a retrospective chart analysis of a randomized national sample of Medicare patients. The study was a part of the National Pneumonia Project, which used fee-for-service hospital claims to identify charts that would be included in the study. A random sample of up to 850 charts per state was established, and abstractors used a computerized tool to record patient demographics and time until the first dose of antibiotics. Death and readmission data were collected from the Medicare enrollment database and Part A claims. Patients were excluded from the study if they did not have radiographic evidence of pneumonia, if there was no documentation of first antibiotic dose timing, if they were immunocompromised, if they did not receive antibiotic therapy within 36 hours of admission, or if they were discharged or died on the day of admission. Main outcomes included severity-adjusted mortality, readmissions within 30 days of discharge, and length of hospital stay.

A sample of 18,209 patients met the inclusion criteria for the study. Of those, 75.6 percent did not receive antibiotic therapy before hospitalization. The remainder of the data is based on the group that had received antibiotics before admission. The in-hospital mortality rate, mortality within 30 days of admission, and length of stay were significantly better in patients who received the first dose of antibiotics within four hours of admission to the hospital. The mean reduction in length of stay was 0.4 days in patients who received early antibiotics compared with those who received them after the four-hour period. The timing of the administration of antibiotics had no impact on readmissions within 30 days after discharge.

The authors conclude that antibiotic administration within four hours of arrival at the hospital in patients with CAP had a positive impact on mortality and length of stay. They add that early administration can reduce in-hospital mortality in the Medicare population and reduce costs, and should be feasible in most patients.