Changing Use of Antibiotics in Community-Based Outpatient Practice, 1991–1999

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The summary below is from the full report titled "Changing Use of Antibiotics in Community-Based Outpatient Practice, 1991-1999." It is in the 1 April 2003 issue of Annals of Internal Medicine (volume 138, pages 525-533). The authors are M.A. Steinman, R. Gonzales, J.A. Linder, and C.S. Landefeld.

What is the problem and what is known about it so far?

Antibiotics are drugs that are effective in treating infections caused by bacteria. Unfortunately, certain bacteria can develop resistance to antibiotics. Resistance means that the antibiotic is no longer effective in treating that type of bacteria. Antibiotic overuse is a concern because it promotes resistant bacteria. Overuse refers to using the antibiotics to treat conditions, such as the common cold, that are not caused by bacteria. Overuse also means using powerful antibiotics that treat a wide range of bacteria (broad-spectrum antibiotics) when a simpler antibiotic would be enough. Antibiotics are among the most common drugs prescribed, and there have been efforts in the United States to get doctors to use them more appropriately. Much of the research on antibiotic use has focused on the hospital setting. Less is known about antibiotic use in doctors' offices.

Why did the researchers do this particular study?

To compare the use of antibiotics for outpatient infections between the early and late 1990s.

Who was studied?

Patients whose visit to the doctor was recorded in the National Ambulatory Medical Survey in 1991–1992, 1994–1995, or 1998–1999. The National Ambulatory Medical Care Survey is a national survey of a sample of patient visits to doctors' offices.

How was the study done?

The researchers looked at the frequency of antibiotic prescription in each of the three time frames. Then they compared antibiotic use in 1991–1992 with use in 1998–1999 for various conditions, including the common cold, sore throat, sinus infections, and bronchitis. Viruses usually cause these conditions, so antibiotics would be unlikely to help patients. The researchers paid particular attention to the use of broad-spectrum antibiotics.

What did the researchers find?

Between 1991–1992 and 1998–1999, the use of antibiotics for outpatient infections decreased. However, the use of broad-spectrum antibiotics doubled in both adults and children during this period.

What were the limitations of the study?

This study was based on survey data and cannot provide information on the reasons that doctors prescribed antibiotics.

What are the implications of the study?

While antibiotic use for ambulatory infections appears to be decreasing, doctors are using more broad-spectrum antibiotics to treat. Efforts to encourage appropriate use of antibiotics should focus not only on when to prescribe antibiotics but also on which antibiotics to use.