Antibiotic Timing in Community-Acquired Pneumonia
Am Fam Physician. 2006 Nov 15;74(10):1781-1782.
Community-acquired pneumonia (CAP) is one of the leading causes of death in the United States and represents a major health care problem. Previous studies of Medicare databases have suggested that the time to the first antibiotic dose has a significant impact on outcomes. Results of these studies had some inconsistencies, one being a higher mortality rate if the antibiotics were administered within two hours of admission. In addition, previous studies have shown that it takes several days of antibiotic use to change the outcomes in pneumococcal pneumonia. Despite these issues, some national regulatory bodies have made the time to the first dose of antibiotics in patients admitted with CAP a benchmark for quality of care. Waterer and associates evaluated the clinical factors that affect the time to the first dose of antibiotics in patients admitted with CAP.
The design of the trial was a prospective cohort study of patients admitted to adult tertiary care hospitals in Memphis, Tenn., between November 1998 and July 2001. To be included in the study, patients had to meet published standards for the diagnosis of acute CAP and have at least one clinical feature of pneumonia (i.e., fever, hypothermia, cough, or sputum production) or two of the following: dyspnea, pleuritic pain, physical findings of consolidation in the lung, or a leukocyte count greater than 12 × 109 cells per L or less than 4.5 × 109 cells per L. Patients were excluded if they had human immunodeficiency virus infection, had received chemotherapy in the previous 60 days, were nonambulatory nursing home residents, or had been hospitalized within the previous 30 days. Data collected were time to the first dose of antibiotic (timed from presentation at triage to first antibiotic dose administered), pneumonia severity index score, presence or absence of septic shock, oxygenation status, and altered mental status.
There were 451 patients enrolled in the study. The average age of the participants was 58.2 years, and 53.3 percent were women. The average time to first antibiotic dose was 285 minutes, with 50.7 percent not receiving the initial dose within four hours. Altered mental status, absence of fever or hypoxia, and increasing age were significant predictors of a time to first dose of antibiotics of greater than four hours. After adjusting for all factors, there was no significant difference in mortality between the group that received antibiotics within the four-hour time frame and those who did not. This was also true in patients who were 65 years or older.
The authors conclude that a delay in the timing of the first dose of antibiotics in patients with CAP is more common in patients with altered mental status or minimal signs of sepsis. They add that the time to administration of the first dose of antibiotic may be a sign of comorbidities driving mortality and an atypical presentation instead of directly contributing to outcomes. Using time to the first dose of antibiotics as an indicator in the care of patients with CAP may be misleading.
Waterer GW, et al. Delayed administration of antibiotics and atypical presentation in community-acquired pneumonia. Chest. July 2006;130:11–5.
editor's note: For the past few years, there has been an attempt to balance the necessary use of antibiotics with limiting usage when possible. With the onset of the new reporting systems for hospitals, the time to first administration of antibiotics in patients with CAP is now being documented. The data are collected on discharge diagnoses. However, what may not present a challenge in diagnosing at the end of a hospitalization may be a challenge on admission. In a similar study by Metersky and colleagues, there were a significant number of patients whose antibiotics were delayed because of the uncertainty of the diagnosis (because of lack of rales, normal oxygenation, and lack of infiltrate on chest radiographs).1 Waterer and associates also found that altered mental status, the absence of fever, and increasing age were associated with delaying antibiotics. Treating patients with an uncertain diagnosis of pneumonia with antibiotics has the potential to result in a significant overuse of antibiotics. In addition, when looking at hospital “report cards” for the care of patients with CAP, the data may not accurately reflect quality of care.—k.e.m.
1. Metersky ML, Sweeney TA, Getzow MB, Siddiqui F, Nsa W, Bratzler DW. Antibiotic timing and diagnostic uncertainty in Medicare patients with pneumonia: Is it reasonable to expect all patients to receive antibiotics within 4 hours?. Chest. 2006;130:16–21.
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