Validation of a decision aid to assist physicians in reducing unnecessary antibiotic drug use for acute cystitis

Abstract

Background: In a previous study, use of a decision aid based on 4 clinical items would have reduced unnecessary antibiotic prescriptions for acute cystitis by 30% compared with usual physician care.

Methods: We assessed the decision aid in a different population of females seen in community-based practice. Between April 7, 2002, and March 20, 2003, 225 Canadian family physicians recorded clinical findings, urine dip test results, and treatment decisions for 331 females with suspected cystitis. The number of decision aid items present was determined for each patient, and the sensitivity and specificity of decision aid recommendations for empirical antibiotics were determined using the gold standard of a positive urine culture result (> or =10(2) colony-forming units per milliliter). Total antibiotic prescriptions, unnecessary prescriptions (for negative culture results), and recommendations for urine cultures were determined and compared with physician management.

Results: Three of the original decision aid variables (dysuria, the presence of leukocytes [greater than a trace amount], and the presence of nitrites [any positive]) were associated with having a positive urine culture result (P < or = .001), but 1 variable (symptoms for 1 day) was not (P = .96). A simplified decision aid incorporating the 3 significant variables (empirical antibiotics without culture if > or =2 variables present; otherwise obtain a culture and wait for results) had a sensitivity of 80.3% (167/208) and a specificity of 53.7% (66/123). Following decision aid recommendations would have reduced antibiotic prescriptions by 23.5%, unnecessary prescriptions by 40.2%, and urine cultures by 59.0% compared with physician care (P < .001 for all).

Conclusion: A simple 3-item decision aid could significantly reduce unnecessary antibiotic drug prescriptions and urine culture testing in females with symptoms of acute cystitis.