Modeling economic implications of alternative treatment strategies for acute bacterial skin and skin structure infections

Figures & data

Figure 1. Overview of model flow.

Figure 2. Treatment strategies for the three cohorts.

Table 1. Model inputs and data sources.

Input parameter	Reference case	Source	Distribution used for PSA
Treatment duration (days)
Vancomycin IV*	10.1	Fan et al.21	Gamma
Linezolid Oral†	10.0	Fan et al.21‡
Daptomycin IV†	13.0	White and Seaton22
Linezolid IV§	10.0	Physicians’ Desk Reference31
Response (at early response assessment)
Empiric therapy	89.4%	Berger et al.25	Beta
Second therapy	100%	Assumption	N/A
Relapse	7%	Berger et al.25	Beta
Mortality risk (per day)	0.10%	LaPensee and Fan5	Beta
ED length of stay (hours)	4.0	Assumption	N/A
Admitted to hospital after ED	60%	LaPensee and Fan5, LaPensee et al.24	N/A
Inpatient length of stay (days)
Abscess/Cellulitis w/empiric failure or relapse	6.4	LaPensee and Fan5	Gamma
Wound infections w/empiric failure or relapse	7.2
Drug acquisition cost (per dose)
Vancomycin IV 1000 mg	$5.46	CMS32	N/A
Linezolid Oral 600 mg	$97.44	American Academy of Pediatrics33
Daptomycin IV 325 mg	$166.18	CMS32
Linezolid IV 600 mg	$111.11	CMS32
Monitoring costs (per test)
Renal Panel	$12.30	CMS32	Lognormal
Vancomycin Trough Levels	$19.19
Complete Blood Count	$9.17
Hepatic Panel	$11.57
CPK Levels	$9.23
PICC line costs
Insertion (procedure and MD fees)	$842.72	CMS34,35	Lognormal
Removal (procedure and MD fees)	$538.05
ED care costs
Visit	$136.05	CMS34,35	Lognormal
Drug infusion (procedure and MD fees)	$180.14
Inpatient care costs (per stay)$
Abscess/Cellulitis w/response to empiric	$4961	Medicare Standard Analytical Files23	Lognormal
Wound infections w/response to empiric	$7258
Abscess/Cellulitis w/second therapy	$10,007
Wound infections w/second therapy	$18,430
Outpatient infusion center care costs
Drug infusion (procedure and MD fees)	$180.14	CMS34,35	Lognormal

*as empiric therapy.

†as ambulatory therapy for responders to empiric.

‡Data from study on file, not published on poster.

§as second antibiotic after treatment failure.

$inflated to 2012 USD.

CPK, creatine phosphokinase; ED, emergency department; IV, intravenous; MD, doctor of medicine; PICC, peripherally inserted central catheter; PSA, Probabilistic sensitivity analysis.

Table 2. Mean total number of days on antibiotic and mean costs per patient accrued in each location of care.

	Treatment strategy
	VAN	LIN	DAP
Total number of days on antibiotic
ED	0.1	0.1	0.1
Inpatient	3.9	4.2	4.5
Outpatient	7.2	9.4	11.6
Total	11.2	13.7	16.2
Costs
ED	$352	$352	$352
Inpatient	$5067	$5062	$5062
Outpatient	$3252	$2094	$4186
Total	$8671	$7508	$9600

DAP, daptomycin; ED, Emergency department; LIN, linezolid; VAN, vancomycin.

Figure 3. ED + inpatient and outpatient costs (per patient) and total days on antibiotic in the outpatient setting as a percentage of patients that are admitted following the first dose in the ED is varied [VAN cohort].

Table 3. Mean total number of days on antibiotic and mean costs per patient—results from scenario analyses for VAN, LIN, and DAP.

Scenario	VAN	LIN	DAP
Reference case
Total days on antibiotic	11.2	13.7	16.2
Total costs	$8671	$7508	$9600
Treatment duration:
Lower bound (VAN 6.4 days, LIN 6.2 days, DAP 10 days)
Total days on antibiotic	7.9	10.4	13.7
Total costs	$7326	$6897	$8725
Upper bound (VAN 13.8 days, LIN 13.8 days, DAP 14 days)
Total days on antibiotic	14.4	16.9	17.1
Total costs	$9819	$8161	$9911
Inpatient DRG costs (median values)
Total days on antibiotic	11.2	13.7	16.2
Total costs	$7986	$6825	$8917
Baseline infection type:
PREMIER data (39.7%–major cutaneous abscess; 39.7%–cellulitis; 0.5%–traumatic wound infection, 20.1%–surgical wound infection)
Total days on antibiotic	11.2	13.7	16.2
Total costs	$8800	$7642	$9735
100% major cutaneous abscess or cellulitis
Total days on antibiotic	11.2	13.7	16.2
Total costs	$8169	$7023	$9735
100% wound infections
Total days on antibiotic	11.2	13.7	16.2
Total costs	$11,209	$10,007	$12,087
Daptomycin administration: two-minute injection
Total days on antibiotic	NR	NR	16.2
Total costs	NR	NR	$8635

DAP, daptomycin; LIN, linezolid; VAN, vancomycin; NR, not relevant.

Figure 4. Results from the PSA (total days on antibiotic and total costs per patient) for each of the 1000 trials for VAN, LIN, and DAP.

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