Asymptomatic bacteriuria, antibiotic use, and suspected urinary tract infections in four nursing homes

BACKGROUND Urinary tract infections (UTIs) are the most commonly treated infection among nursing home residents. Even in the absence of specific (e.g., dysuria) or non-specific (e.g., fever) signs or symptoms, residents frequently receive an antibiotic for a suspected infection. This research investigates factors associated with the use of antibiotics to treat asymptomatic bacteriuria (ASB) among nursing home residents. METHODS This was a cross-sectional study involving multi-level multivariate analyses of antibiotic prescription data for residents in four nursing homes in central Texas. Participants included all nursing home residents in these homes who, over a six-month period, received an antibiotic for a suspected UTI. We investigated what factors affected the likelihood that a resident receiving an antibiotic for a suspected UTI was asymptomatic. RESULTS The most powerful predictor of antibiotic treatment for ASB was the presence of an indwelling urinary catheter. Over 80 percent of antibiotic prescriptions written for catheterized individuals were written for individuals with ASB. For those without a catheter, record reviews identified 204 antibiotic prescriptions among 151 residents treated for a suspected UTI. Almost 50% of these prescriptions were for residents with no documented UTI symptoms. Almost three-quarters of these antibiotics were ordered after laboratory results were available to clinicians. Multivariate analyses indicated that resident characteristics did not affect the likelihood that an antibiotic was prescribed for ASB. The only statistically significant factor was the identity of the nursing home in which a resident resided. CONCLUSIONS We confirm the findings of earlier research indicating frequent use of antibiotics for ASB in nursing homes, especially for residents with urinary catheters. In this sample of nursing home residents, half of the antibiotic prescriptions for a suspected UTI in residents without catheters occurred with no documented signs or symptoms of a UTI. Urine studies were performed in almost all suspected UTI cases in which an antibiotic was prescribed. Efforts to improve antibiotic stewardship in nursing homes must address clinical decision-making solely on the basis of diagnostic testing in the absence of signs or symptoms of a UTI.