Comparing ceftolozane/tazobactam versus piperacillin/tazobactam as empiric therapy for complicated urinary tract infection in Taiwan: A cost-utility model focusing on gram-negative bacteria

Background: Complicated urinary tract infection (cUTI) is often associated with drug-resistant pathogens and requires therapy with broad-spectrum antibiotics. Choice of empiric therapy should be based on an evaluation of clinical efficacy and medical costs. We used a cost-utility model to compare the empiric use of a new antibiotic, ceftolozane/tazobactam with piperacillin/tazobactam in patients with cUTI. Methods: The analysis was conducted using a decision tree and patient-level simulation approach. Patients in the model received empiric antibiotic treatment with ceftolozane/tazobactam or piperacillin/tazobactam. Outcomes included mortality, medical costs and quality-adjusted life years (QALYs). Parameters related to pathogen distribution, length of hospital stay and medical costs, were estimated based on a cohort of patients with cUTI admitted during July 1st, 2015 to August 31st, 2016 to the National Taiwan University Hospital, a teaching hospital in Taiwan. Isolates used for the patient-level simulation to determine susceptibility to either drug were taken from the Study for Monitoring Antimicrobial Resistance Trend database. Results: The analysis was performed on a simulation of 1000 patients. Empiric use of ceftolozane/tazobactam leads to higher total medical costs (USD 4199.01 per patient versus USD 3594.76, respectively) but also more discounted QALYs (4.80 versus 4.78, respectively). The additional cost per discounted QALY gained associated with empiric ceftolozane/tazobactam was 32,521.08 USD (956,282 NTD). Conclusions: Our results suggest that empiric use of ceftolozane/tazobactam for the treatment of cUTI could be a cost-effective choice in Taiwan. ? 2019