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  • Publication # 13-RA008

Use of antibiotics is common among older adults and varies across regions

Patient Safety and Quality

Image of pills The use of antibiotics among Medicare beneficiaries varies across regions, after controlling for differences in patient characteristics, reveals a new study. These regional differences did not seem to be explained simply by differences in the prevalence of underlying conditions, because regions with high use of antibiotics often had lower rates of bacterial pneumonia diagnosis. Antibiotic use rates were highest in the South (21.4 percent per quarter) and lowest in the West (17.4 percent per quarter). 

There were also significant quarterly differences in antibiotic use, with the highest rates during the first 3 months of the year, and the lowest rates during the third quarter (July through September). The Northeast had the highest prevalence of bacterial pneumonia, despite having the lowest use of antibiotics, while the South, with the highest antibiotic use rates, had the highest prevalence of nonspecific acute respiratory tract infections, which are often due to viruses not treatable by antibiotics.

This study looked at national data for 2007 through 2009 from three distinct levels: 

  1. The 306 hospital referral regions identified by the Dartmouth Atlas of Health Care.
  2. The 50 States plus the District of Columbia.
  3. Four national regions (South, West, Midwest, and Northeast).

 In addition to bacterial pneumonia, acute nasopharyngitis and other acute respiratory tract infections were included. This study was supported in part by AHRQ (HS18657).

See "Geographic Variation in outpatient antibiotic prescribing among older adults," by Yuting Zhang, Ph.D., Michael A. Steinman, M.D., and Cameron M. Kaplan, Ph.D., in the October 22, 2012 Archives of Internal Medicine 172(19), pp. 1465-1471.


Page last reviewed May 2013
Internet Citation: Use of antibiotics is common among older adults and varies across regions: Patient Safety and Quality. May 2013. Agency for Healthcare Research and Quality, Rockville, MD.


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