Background: Approximately 7 million patients visit a health care professional in the United States each year for uncomplicated urinary tract infections (UTIs). Most receive prescriptions for trimethoprim/sulfamethoxazole (TMP-SMX [Bactrim, Septra]), ciprofloxacin (Cipro), or nitrofurantoin (Furadantin). Because of potential bacterial resistance to fluoroquinolones and rising medical costs, the Infectious Diseases Society of America (IDSA) published guidelines in 1999 that recommended TMP-SMX as first-line therapy for uncomplicated UTI. In a cross-sectional study, Taur and Smith evaluated whether prescribing habits for UTI changed after the guidelines were published.

The Study: The authors reviewed data from National Ambulatory Medical Care and National Hospital Ambulatory Care Surveys collected before and after the publication of the guidelines. Using International Classification of Diseases, Ninth Revision, Clinical Modification codes for UTI or acute cystitis, data were analyzed by office site (i.e., private offices or hospital clinics), patient age, patient race, geographic location, prescriber specialty, and patient payment method. Data from emergency department visits were not included.

Results: During the study (1996 to 2001), TMP-SMX and ciprofloxacin were most commonly prescribed, followed by nitrofurantoin. Although TMP-SMX and nitrofurantoin use did not change significantly after the introduction of the guidelines, ciprofloxacin use increased by 66 percent. Similar results were found after controlling for the aforementioned variables. However, hospital-based physicians and generalists were more likely to prescribe TMP-SMX than physicians in private offices; and younger, nonwhite, or self-pay patients were more likely to be prescribed TMP-SMX than ciprofloxacin or nitrofurantoin.

Conclusion: The authors conclude that physicians are not following the IDSA guidelines for treating uncomplicated UTI, which may contribute to rising medical costs and bacterial resistance to fluoroquinolones. These results raise questions about what factors prompt physicians to change their prescribing habits.

editor's note: This study raises two concerns. First, is the trend away from prescribing TMP-SMX for UTI adversely affecting resistance to antibiotics and medical costs? The study was not designed to address this question, but it would be a logical next research step. Updated and comprehensive information about Escherichia coli resistance to TMP-SMX and ciprofloxacin could help focus this discussion because physicians may base prescribing on perceived or reported rates of resistance in their communities.

The second concern is the apparent non-adherence to the guidelines. An accompanying editorial discusses the study's inability to determine individual physician exposure to and knowledge of the guidelines and how they were applied in individual cases.¹ Taur and Smith assume that hospital-based clinics, which are more likely to support residency programs, may have physicians who are more comfortable with evidence-based medicine and more up to date with published guidelines than are physicians in private offices. The study highlights the broader issue of disseminating and applying guidelines after they are published.—a.c.f.