Antibiotic Overuse Persists

Steven Fox

September 24, 2012

September 24, 2012 — Two large studies carried out in the United States provide striking perspectives on the continuing problem of antibiotic overuse.

Both articles were published online September 24 in the Archives of Internal Medicine.

In the first article, the researchers studied geographic variations in antibiotic prescribing among older adults.

"Antibiotic use variation in the non-Medicare population has been investigated, but little is known about the antibiotic prescribing patterns among older adults," Yuting Zhang, PhD, from the Graduate School of Public Health, University of Pittsburgh, Pennsylvania, and colleagues write.

Medicare Part D drug benefits were instituted in 2006, and since then, considerable data on antibiotic prescribing for older adults have been accumulating. "However, to our knowledge, no study to date using Medicare Part D data has examined variation in antibiotic use among older adults," the researchers write.

Aiming to help fill that gap in knowledge, these researchers evaluated Medicare Part D data for the years 2007 through 2009.

Using the residential Zip codes of Medicare beneficiaries, the researchers checked for regional prescribing trends in several ways: state-by-state (plus the District of Columbia), by 4 national regions (Northeast, South, West, and Midwest), and by assessing data from the 306 Dartmouth Atlas of Health Care hospital referral regions. They also evaluated how antibiotic prescribing varied by seasonal quarters.

The investigators adjusted across all regions for differences in patient demographics and insurance status, as well as for clinical characteristics.

Antibiotics in Older Adults

The South accounted for the highest antibiotic use, with, on average, 21.4% of patients each quarter being prescribed an antibiotic. Patients in Western states received antibiotics the least, at about 17.4% of patients per quarter (P < .01).

Across all regions, antibiotic prescribing peaked during the first quarter (January - March), at 20.9%, and was lowest during the third quarter (July - September), at 16.9%, the researchers say (P < .01).

The variations, the researchers state, could not be explained by differences in the prevalence of infections between regions and across seasonal quarters. Regions with high use of antibiotics often had lower rates of bacterial pneumonia, the authors report.

They note that geographic areas with high antibiotic use would likely benefit from programs aimed at reducing unnecessary usage of the drugs, and they emphasize that although seniors may be at higher risk for adverse outcomes when they have bacterial infections, they may also be at higher risk for adverse effects from antibiotics. "Therefore, it might be necessary to target some quality improvement initiatives toward this age group," they conclude.

Study limitations include the inability to control for disease severity and other factors that may have biased the data.

Antibiotics for Sinusitis

In the other study, presented in a research letter also published online September 24, a group of researchers studied national trends in antibiotic prescribing for adults in the United States who were diagnosed with acute sinusitis.

The principal finding was that even though most sinusitis is viral in origin and antibiotics are of little use in treating such infections, the prescribing of broad-spectrum antibiotics, such as quinolones and macrolides, is extremely common.

Tarayn Fairlie, MD, MPH, from the Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, and colleagues note that up until 2012, amoxicillin was the recommended empirical treatment for acute bacterial sinusitis. New guidelines now recommend amoxicillin-clavulanate.

"In light of recent studies and new treatment guidelines, we sought to examine visit rates and antibiotic prescribing patterns for adults with acute sinusitis in the United States," they write.

Using 2000 to 2009 data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, along with standard diagnostic criteria from the International Classification of Diseases, Ninth Revision, Clinical Modification, the authors estimated the annual number of acute sinusitis visits per 1000 adults in the United States.

As primary outcomes measures, they used the proportion of office visits for acute sinusitis in which any antibiotic was prescribed, as well as the proportion of antibiotic visits in which amoxicillin was prescribed.

They excluded visits that had concomitant diagnoses (eg, urinary tract infections) that might require antibiotics. Also excluded were visits that resulted in hospitalizations and visits in which patients were prescribed vancomycin or an aminoglycoside.

"In the present study, using a nationally representative data set of ambulatory visits, we found that more than 80% of patients diagnosed as having acute sinusitis receive an antibiotic, despite mounting evidence that the benefits of antibiotic treatment for sinusitis are limited," the authors write.

More specifically, they found that antibiotics were prescribed in 83% (95% confidence interval [CI], 78% - 86%) of visits for acute sinusitis and that that rate of prescribing did not change significantly during the study period (P = .85).

Amoxicillin, the recommended agent during the period studied, was prescribed in only 17% (95% CI, 12% - 23%) of cases. The other most commonly prescribed antibiotics were macrolides (29%), quinolones (19%), and amoxicillin-clavulanate (16%).

"Changes in prescribing behavior of health care providers for sinusitis are urgently needed to improve health care quality and stem the rising tide of antibiotic resistance in the United States," the authors conclude.

Translating Public Health Priorities

In an invited commentary by Ralph Gonzales, MD, MSPH, from the Department of Medicine and the Department of Epidemiology, University of California, San Francisco, and colleagues, the authors write, "We believe that the persistence of antibiotic overuse in the United States is a failure to translate national public health priorities and evidence into local practice and policies. We ask whether the application of recent implementation frameworks could help to guide more successful evidence translation and provide a sharper focus for future intervention activities."

With that idea in mind, they developed a checklist aimed at assessing the likelihood of clinicians being able to successfully translate evidence into practice when dealing with a specific problem area — in this case, antibiotic overuse.

The checklist is adapted from 2 sources: a national study that empirically assessed high-performance medical delivery systems and a Consolidated Framework for Implementation Research.

The checklist contains 3 domains: Significance of the Problem Area, Organization and Stakeholder Readiness for Change, and Feasibility of Intervention. Each domain is composed of several questions. For each of the questions, these authors came up with a general summary rating (favorable, unfavorable, or neutral) describing the effect it might have on efforts to implement more judicious antibiotic use.

Hurdles exist in all 3 domains of the checklist, the authors say, but they also note that previous research has shown that coordinated, multidimensional interventions can help cut down on antibiotic overuse in local delivery systems.

They reason, then, that particularly tough challenges in the first 2 domains (Significance of the Problem Area and Organization and Stakeholder Readiness for Change) may help explain why proven interventions have so far not been more widely disseminated and adopted.

"We need to find better ways to compel individuals and organizations to address the significance of the problem of antibiotic overuse and to increase the readiness for change and quality improvement of ambulatory practices in the United States," they conclude.

The Zhang study was funded in part by the Centers for Medicare and Medicaid Services, the Institute of Medicine, the National Institute of Mental Health, the Agency for Healthcare Research and Quality, the National Institute on Aging, and the American Federation for Aging Research. The authors of both studies and the editorialists have disclosed no relevant financial relationships.

Arch Intern Med. Published online September 24, 2012.

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