Cost-Effectiveness of Strategies to Prevent Methicillin-Resistant Staphylococcus aureus Transmission and Infection in an Intensive Care Unit

Courtney A. Gidengil, MD, MPH; Charlene Gay, BA; Susan S. Huang, MD, MPH; Richard Platt, MD, MS; Deborah Yokoe, MD, MPH; Grace M. Lee, MD, MPH

Disclosures

Infect Control Hosp Epidemiol. 2015;36(1):17-27.

Abstract and Introduction

Abstract

Objective To create a national policy model to evaluate the projected cost-effectiveness of multiple hospital-based strategies to prevent methicillin-resistant Staphylococcus aureus (MRSA) transmission and infection.

Design Cost-effectiveness analysis using a Markov microsimulation model that simulates the natural history of MRSA acquisition and infection.

Patients and Setting Hypothetical cohort of 10,000 adult patients admitted to a US intensive care unit.

Methods We compared 7 strategies to standard precautions using a hospital perspective: (1) active surveillance cultures; (2) active surveillance cultures plus selective decolonization; (3) universal contact precautions (UCP); (4) universal chlorhexidine gluconate baths; (5) universal decolonization; (6) UCP + chlorhexidine gluconate baths; and (7) UCP+decolonization. For each strategy, both efficacy and compliance were considered. Outcomes of interest were: (1) MRSA colonization averted; (2) MRSA infection averted; (3) incremental cost per colonization averted; (4) incremental cost per infection averted.

Results A total of 1989 cases of colonization and 544 MRSA invasive infections occurred under standard precautions per 10,000 patients. Universal decolonization was the least expensive strategy and was more effective compared with all strategies except UCP+decolonization and UCP+chlorhexidine gluconate. UCP+decolonization was more effective than universal decolonization but would cost $2469 per colonization averted and $9007 per infection averted. If MRSA colonization prevalence decreases from 12% to 5%, active surveillance cultures plus selective decolonization becomes the least expensive strategy.

Conclusions Universal decolonization is cost-saving, preventing 44% of cases of MRSA colonization and 45% of cases of MRSA infection. Our model provides useful guidance for decision makers choosing between multiple available hospital-based strategies to prevent MRSA transmission.

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Abstract and Introduction
Background
Methods
Results
Discussion
References

Table 1. Model Variables: Baseline Values and Ranges Used in Sensitivity Analyses
Variable	Base case	Distribution	Source(s)
Disease costs
Cost of MRSA colonization	$0		N/A
Average attributable LOS in days of MRSA infection during hospitalization
CAUTI	0 ICU/1 ward	Log normal	7,30–34
CLABSI	2 ICU/5 ward
SSI	3 ICU/4 ward
VAP	3 ICU/5 ward
Average ICU LOS if no MRSA infection	3 days	Log normal	35
Average overall LOS if no MRSA infection	5 days	Log normal	35
Cost per hospital day (ICU)	$4285	Log normal	36
Cost per hospital day (general ward)	$969	Log normal	Calibrated to model
Daily cost of treatment of invasive MRSA infection after hospital discharge	$248	Log normal	37
Total days in treatment course			Expert consensus
CAUTI	7	Log normal
CLABSI	14
SSI	14
VAP	10
Cost per episode of MRSA infection in outpatient settinga	$375	Log normal	17,38,39
Intervention costs
Cost of contact precautions per day	$125 per day	Log normal	40
Cost of ASC test	$13 per test	Log normal	26,27
Cost of CHG bath per day	$11 per day	Log normal	17
Cost of decolonization (CHG + mupirocin) per day	$23 per day	Log normal	17
Intervention estimates
ASC with selective CP
Efficacy for preventing colonization	(tied to efficacy for universal CP)	Beta	22,41–43
Efficacy for preventing infection	…		44
Compliance	95%
ASC with selective decolonization
Efficacy for preventing colonization	94%	Beta
Efficacy for preventing infection	…
Compliance	80%		23,45
Universal CP
Efficacy for preventing colonization	94%	Beta	46
Efficacy for preventing infection
Compliance	47%		21,47–51
Universal CHG
Efficacy for preventing colonization	38%	Beta	52
Efficacy for preventing infection	35%		Expert consensus
Compliance	88%		53,54
Universal decolonizationb
Efficacy for preventing colonization	60%	Beta	Expert consensus
Efficacy for preventing infection	50%		25
Compliance	88%		25
ASC characteristics
Sensitivity of ASC testingc	64%		55,56 and expert consensus
Specificity of ASC testing	96%		55,56
Prevalence/incidence parameters
MRSA colonization at ICU admission	12%	Beta	21,41,52,57–64
MRSA infection at ICU admission	0.6%	Beta	65,66
Risk of acquiring MRSA colonization per hospitalization day among non-colonized patients based on prevalence (prevalence − risk of acquiring MRSA colonization)	0%–0.0%	Log normal	41,52,57–59
	3%–0.2%
	6%–0.4%
	9%–0.6%
	12%–0.9%
	15%–1.1%
	18%–1.3%
	21%–1.5%
Risk of developing MRSA infection per hospitalization day among colonized patients	0.6%	Beta	15,16,59,67
Type of MRSA infection
CAUTI	4%	…	19
CLABSI	23%
SSI	43%
VAP	30%
Cumulative probability of death due to MRSA infection
CAUTI	0%	…	5,6,8,18,68–70
CLABSI	21%
SSI	24%
VAP	30%
Daily probability of death due to other causes
General ward	0.01%	…	Expert consensus
ICU	3%
Outpatient
Risk of developing MRSA infection per outpatient day among colonized patients
<3 months	0.15%	Triangular	15,16
3to <6 months	0.09%
6to ≤12 months	0.04%
Probability of requiring hospitalization if develop an outpatient MRSA infection	47%	Triangular	15,16

NOTE. ASC, active surveillance cultures; CAUTI, catheter-associated urinary tract infection; CHG, chlorhexidine gluconate; CLABSI, central line-associated bloodstream infection; CP, contact precautions; ICU, intensive care unit; LOS, length of stay; MRSA, methicillin-resistant Staphylococcus aureus; SSI, surgical site infections; VAP, ventilator-associated pneumonia.
^aBased on cost of skin and soft tissue infections.
^bWe based the estimates for efficacy for preventing infection and compliance with the intervention from the trial from reference 25 (extrapolating from the effectiveness result presented in the trial). We then used expert consensus to judge the possible efficacy for colonization based on these estimates.
^cWe assume that patients are receiving nares swabs only. Per expert consensus, we took an estimate of 92% from the literature for detection of MRSA from culture under perfect conditions, and multiplied that by 70% to reflect the sensitivity of nares swabs to detect MRSA colonization.

Table 2. Incremental Cost per Colonization and Infection Averted per 10,000 Intensive Care Unit Admissions for Alternative Strategies Using Base Case Assumptions
Strategy	Total costs (in millions)	Disease costs (in millions)	Intervention costs (in millions)	Cases of colonization averted	Cases of infection averted	Incremental cost per colonization averted	Incremental cost per infection averted
Universal decolonization	$5.35	$4.57	$0.78	870	246	…	…
ASC testing plus selective decolonization	$5.36	$4.83	$0.54	794	224	Dominated	Dominated
Universal CHG	$5.91	$5.65	$0.26	601	171	Dominated	Dominated
UCP + decolonization	$5.94	$3.62	$2.33	1107	312	$2469	$9007
UCP + universal CHG	$6.30	$4.49	$1.81	890	250	Dominated	Dominated
ASC testing alone	$6.56	$6.03	$0.53	521	144	Dominated	Dominated
Universal CP alone	$8.15	$6.58	$1.57	387	107	Dominated	Dominated
Standard precautions	$8.16	$8.16	…	…	…	Dominated	Dominated

NOTE. Under standard precautions, 1989 and 544 cases of MRSA colonization and infection would occur, respectively. ASC, active surveillance cultures; CHG, chlorhexidine gluconate; CP, contact precautions.

Appendix A. Incremental Cost per Colonization and Infection Averted per 10,000 Intensive Care Unit Admissions for Alternative Strategies under Assumption that Methicillin-Resistant *Staphylococcus aureus* Prevalence Is 5%
Strategy	Total costs (in millions)	Disease costs (in millions)	Intervention costs (in millions)	Cases of colonization averted	Cases of infection averted	Incremental cost per colonization averted	Incremental cost per infection averted
ASC testing plus selective decolonization	$2.06	$1.65	$0.41	437	135	…	…
Universal decolonization	$2.34	$1.50	$0.84	472	143	$8233	$36,020
Universal CHG	$2.46	$2.16	$0.29	303	87	Dominated	Dominated
ASC testing alone	$2.70	$2.30	$0.40	283	83	Dominated	Dominated
Standard precautions	$3.27	$3.27	…	…	…	Dominated	Dominated
UCP + universal CHG	$3.68	$1.59	$2.09	473	133	Extended dominance	Dominated
UCP + universal decolonization	$3.79	$1.16	$2.63	597	172	$834	$49,724
UCP alone	$4.20	$2.39	$1.80	219	70	Dominated	Dominated

NOTE. ASC, active surveillance cultures; CHG, chlorhexidine gluconate; UCP, universal contact precautions.

Appendix B. Incremental Cost per Colonization and Infection Averted per 10,000 Intensive Care Unit Admissions for Alternative Strategies under Assumption that Methicillin-Resistant *Staphylococcus aureus* Prevalence Is 20%
Strategy	Total costs (in millions)	Disease costs (in millions)	Intervention costs (in millions)	Cases of colonization averted	Cases of infection averted	Incremental cost per colonization averted	Incremental cost per infection averted
Universal decolonization	$6.57	$5.73	$0.84	1752	543	…	…
UCP + universal decolonization	$6.81	$4.17	$2.64	2079	644	$719	$2329
ASC testing plus selective decolonization	$7.68	$6.97	$0.71	1513	468	Dominated	Dominated
UCP + universal CHG	$8.25	$6.13	$2.12	1601	513	Dominated	Dominated
Universal CHG	$8.48	$8.18	$0.30	1183	377	Dominated	Dominated
ASC testing alone	$10.91	$10.21	$0.70	817	261	Dominated	Dominated
UCP alone	$12.94	$11.08	$1.86	596	192	Dominated	Dominated
Standard precautions	$13.95	$13.95	…	…	…	Dominated	Dominated

NOTE. ASC, active surveillance cultures; CHG, chlorhexidine gluconate.

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Cost-Effectiveness of Strategies to Prevent Methicillin-Resistant Staphylococcus aureus Transmission and Infection in an Intensive Care Unit

Abstract and Introduction

Abstract

Tables

Tables

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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