Impact of an antimicrobial stewardship intervention on clinical and economic outcomes in outpatient parenteral antimicrobial therapy (OPAT) for urinary tract infections: A quasi-experimental study.

INTRODUCTION

Urinary tract infections (UTIs) are a common indication for Outpatient Parenteral Antimicrobial Therapy (OPAT) and often involved prolonged intravenous (IV) treatments. A theory-informed Antimicrobial Stewardship (AMS) intervention was implemented to optimize antibiotic duration and promote IV-to-oral switching in OPAT patients with UTIs.

METHODS

This pre-post quasi-experimental single-centre study included adults with UTIs managed through OPAT. The intervention was designed using behaviour change techniques, and structured as a bundle of quality improvement strategies to optimize antibiotic prescribing.

PRIMARY OUTCOMES: (1) the proportion of patients receiving appropriate treatment duration and (2) the proportion of those with microbiological confirmation and an oral option, who were switched to oral.

SECONDARY OUTCOMES: adverse events, 90-day recurrence and readmission, healthcare resource consumption.

RESULTS

A total of 314 patients were included. Post-intervention patients were more often male, and with a history of recurrent UTI. Other baseline characteristics were comparable. Appropriate antibiotic duration increased from 44.4% (baseline) to 83.3% (intervention period) (p ≤ .001), IV-to-oral switch rates from 62.8% to 85.7% (p ≤ .001). In adjusted analyses, the intervention was independently associated with appropriate duration (OR 6.70, 95% CI 3.79-11.85), IV-to-oral switching (OR 3.57, 95% CI 1.56-8.19), fewer 90-days UTI recurrences (OR 0.41, 95% CI 0.21-0.80) and no increase in 90-days readmissions. A significant reduction in healthcare cost was achieved with a median difference of -648.8€ (95% CI -1050.0 to -247.7).

CONCLUSIONS

A structured AMS intervention for UTIs in OPAT improved appropriate antibiotic duration, increased IV-to-oral switching, and reduced healthcare costs without compromising clinical safety. Behaviour-informed stewardship strategies can optimize antimicrobial use in OPAT care.