Failures in prescription stewardship : understanding the clinical, patient, and physician factors associated with the inappropriate treatment of asymptomatic bacteriuria with antimicrobial therapies

OF THE THESIS Failures in Prescription Stewardship: Understanding the Clinical, Patient, and Physician Factors Associated with the Inappropriate Treatment of Asymptomatic Bacteriuria with Antimicrobial Therapies by Casey Dunne Master of Public Health with a Concentration in Epidemiology San Diego State University, 2013 Background: Prevalence of asymptomatic bacteriuria (ASB) in the entire community is approximately 3.5%. ASB is not associated with increased mortality, and, except in special populations, the Infectious Disease Society of America (IDSA) recommends that ASB not be treated with antimicrobials. Non-adherent treatment and unnecessary exposure to antimicrobials puts patients at risk for serious adverse clinical outcomes such as Clostridium difficile infection (CDI), which results in increased costs for patients and healthcare facilities. Increased age and pyuria are known risk factors for non-adherent treatment of ASB and will be analyzed in this study. Existing literature about the location of a physician’s medical school training is not substantial, so it will be a novel risk factor in this study. Purpose: A retrospective study of patients 18 or older with positive urine cultures was completed in order to understand the association of three risk factors with non-adherent treatment of ASB. This study hypothesized that non-adherent treatment was associated with being elderly (80 or older), having pyuria, and having a physician who was trained outside the United States/Canada. Methods: Data were obtained through review of medical records at Scripps Mercy San Diego for patients with positive urine cultures between January 1, 2012 and April 30, 2012. Following univariate analysis, multivariate analysis using backward stepwise logistic regression eliminated variables that were not associated with non-adherent treatment. Results: Of the 199 ASB patients, 59.3% of patients received non-adherent treatment. When looking at risk factors of interest, 34.2% were 80 years old or older, 17.1% were positive for pyuria, and 19.1% of treating physicians went to medical school outside of the U.S. or Canada. Non-adherent treatment was significantly associated with two risk factors of interest: age of 80 years or more (OR 2.43; 95% CI 1.22, 4.86; p=0.0118) and pyuria (OR 3.41; 95% CI 1.31, 8.86; p=0.0119), after adjusting for other covariates. The third risk factor of interest, location of physician medical school training, was not significantly associated with nonadherently. One covariate, length of stay, was significantly associated with non-adherent treatment. After adjusting for age and pyuria, patients who received non-adherent treatment were less likely to have stayed five days or more in the hospital (OR 0.30; 95% CI 0.16, 0.58; p=0.0003). Conclusions: Patient age and pyuria continue to be important risk factors for non-adherent treatment of ASB according to IDSA guidelines. Although experience and clinical judgment should contribute to diagnosis and treatment, physicians must carefully analyze culture results along with urinalyses and symptomology in order to determine the best possible courses for patients.