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Clinical decision system helps reduce inappropriate antimicrobial prescribing

November 09, 2005

A clinical decision support system intervention reduced the overall use of antimicrobials for respiratory tract infections such as colds, bronchitis and sinusitis, according to a study in the November 9 issue of JAMA.

Antimicrobial resistance is a serious public threat that is exacerbated by the gradual withdrawal of the pharmaceutical industry from new antimicrobial agent development, according to background information in the article. Overuse of antimicrobial agents fosters the spread of antimicrobial-resistant organisms. Despite recent trends that demonstrate reduced outpatient use of antimicrobial agents, prescribing continues to significantly exceed prudent levels. Approximately 50 percent of courses of ambulatory antimicrobial drugs are prescribed for patients with viral respiratory infections and therefore, are not clinically indicated.

Matthew H. Samore, M.D., of the University of Utah, Salt Lake City, and colleagues evaluated the effectiveness of a direct intervention with primary care clinicians that was used to reduce the rate of inappropriate prescribing of antimicrobial drugs for acute respiratory infections. The intervention, the clinical decision support system (CDSS), incorporated stand-alone decision support tools on paper and a handheld personal digital assistant (PDA) to guide diagnosis and management of the acute respiratory tract infection. The researchers measured the added value of the CDSS when coupled with a community intervention.

The PDA-based CDSS generated diagnostic and therapeutic recommendations on the basis of patient-specific information that was input about the suspected diagnosis, such as the presence or absence of specific symptoms and signs. Therapeutic recommendations included over-the-counter medications for symptom control as well as prescription antimicrobials. In the study, antimicrobial agents were grouped into 4 classes: penicillins, macrolides, cephalosporins, and other.

The randomized trial included 407,460 inhabitants and 334 primary care clinicians in 12 rural communities in Utah and Idaho and a third group of 6 communities that served as nonstudy controls. The pre-intervention period was January to December 2001 and the postintervention period was January 2002 to September 2003. Six communities received a community intervention alone and 6 communities received community intervention plus CDSS that were targeted toward primary care clinicians. Community-wide antimicrobial usage was assessed using retail pharmacy data. Diagnosis-specific antimicrobial use was compared by chart review.

Within CDSS communities, 71 percent of primary care clinicians participated in the use of CDSS. The researchers found that during the second-intervention year, prescribing rates in CDSS communities decreased 10 percent from baseline, whereas in the community intervention?alone communities and nonstudy communities, prescribing rates in 2003 increased by 1 percent and 6 percent, respectively. The prescribing rate decreased from 84.1 to 75.3 per 100 person-years in the CDSS group vs. 84.3 to 85.2 in community intervention alone, and remained stable in the other communities. A total of 13,081 acute respiratory infection visits were documented for this study. The relative decrease in antimicrobial prescribing for visits in the antibiotics "never-indicated" category during the post-intervention period was 32 percent in CDSS communities and 5 percent in community intervention-alone communities. Use of macrolides decreased significantly in CDSS communities but not in community intervention-alone communities.

"This trial demonstrated the feasibility, uptake, and benefit of stand-alone, portable CDSS tools for acute respiratory infections in rural primary care settings. The CDSS decreased unnecessary use of antimicrobial agents for viral respiratory tract infections and improved antimicrobial agent selection," the authors write.

"An unresolved question is whether the modest decrease in total antimicrobial prescriptions and more substantial reduction in macrolide use induced by the CDSS intervention was sufficient to lessen selection of resistant pneumococci and other bacteria in community populations. Decreased prevalence of resistant organisms may not necessarily accompany lowered antimicrobial consumption, in part because resistant organisms have an ability to develop compensatory mutations that ameliorate the fitness costs of resistance. More potent interventions that sustain greater improvements in antimicrobial use may be needed to adequately control antimicrobial resistance," the researchers conclude.

JAMA and Archives Journals