Cost-effectiveness of ceftolozane/tazobactam plus metronidazole versus piperacillin/tazobactam as initial empiric therapy for the treatment of complicated intra-abdominal infections based on pathogen distributions drawn from national surveillance data in the United States

Table 1 Clinical and economic inputs

Input Parameters	Mean	Lower bound	Upper bound	Source
Mortality rate with appropriate empiric treatment	0.013	0.012	0.014	Edelsberg et al. [13]
Mortality rate with inappropriate empiric antibiotic	0.095	0.086	0.105	Edelsberg et al. [13]
Duration of empiric therapy	3 days	3 days	3 days	Assumption
Total LOS for IAAT (inc. empiric therapy)	6.9 days	6.8 days	7 days	Edelsberg et al. [13]
Total LOS for IIAT (inc. empiric therapy)	11.5 days	11.3 days	11.9 days	Edelsberg et al. [13]
Health utility for survivors	0.85	0.70	1.00	Assumption based on Jansen et al. [25]
Discount rate	3.0%	3.0%	3.0%	AMCP [26]
Hospital cost per day (average)	$2558.55	$2046.84	$3070.26	HCUP [27]
Drug acquisition costs per day
Ceftolozane/tazobactam plus metronidazole	$253.20			Analy$ource [29]
Aztreonam	$84.24			Analy$ource [29]
Cefepime	$23.04			Analy$ource [29]
Ceftazidime	$36.66			Analy$ource [29]
Ceftriaxone	$6.40			Analy$ource [29]
Ciprofloxacin	$5.26			Analy$ource [29]
Doripenem	$125.22			Analy$ource [29]
Imipenem	$73.12			Analy$ource [29]
Levofloxacin	$6.24			Analy$ource [29]
Meropenem	$81.51			Analy$ource [29]
Piperacillin/tazobactam	$43.08			Analy$ource [29]
Tigecycline	$238.34			Analy$ource [29]
Salvage^a	$164.31			Analy$ource [29]
Health care expenditure incurred per year
<25 years	$477			Basu [18]
25 to 34 years	$790			Basu [18]
35 to 44 years	$947			Basu [18]
45 to 54 years	$1422			Basu [18]
55 to 64 years	$2106			Basu [18]
65 to 74 years	$2758			Basu [18]
75 years and above	$3100			Basu [18]

^aSalvage therapy consists of meropenem + colistin for cost purposes
LOS Length of stay, IAAT Initial appropriate antibiotic therapy, IIAT Initial inappropriate antibiotic therapy