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 CLABSI SSI VAP |
0 ICU/1 ward 2 ICU/5 ward 3 ICU/4 ward 3 ICU/5 ward |
Log normal |
7,30–34 |
| 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 CAUTI CLABSI SSI VAP |
7 14 14 10 |
Log normal |
Expert consensus |
| Cost per episode of MRSA infection in outpatient setting* | $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 Efficacy for preventing infection Compliance |
(tied to efficacy for universal CP) -- 95% |
Beta |
22,41–43 44 |
| ASC with selective decolonization Efficacy for preventing colonization Efficacy for preventing infection Compliance |
94% -- 80% |
Beta |
23,45 |
| Universal CP Efficacy for preventing colonization Efficacy for preventing infection Compliance |
94% -- 47% |
Beta |
46 21,47–51 |
| Universal CHG Efficacy for preventing colonization Efficacy for preventing infection Compliance |
38% 35% 88% |
Beta |
52 Expert consensus 53,54 |
| Universal decolonization** Efficacy for preventing colonization Efficacy for preventing infection Compliance |
60% 50% 88% |
Beta |
Expert consensus 25 25 |
| ASC characteristics | |||
| Sensitivity of ASC testing*** | 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% 3% – 0.2% 6% – 0.4% 9% – 0.6% 12% – 0.9% 15% – 1.1% 18% – 1.3% 21% – 1.5% |
Log normal | 41,52,57–59 |
| Risk of developing MRSA infection per hospitalization day among colonized patients |
0.6% | Beta | 15,16,59,67 |
| Type of MRSA infection CAUTI CLABSI SSI VAP |
4% 23% 43% 30% |
-- |
19 |
| Cumulative probability of death due to MRSA infection CAUTI CLABSI SSI VAP |
0% 21% 24% 30% |
-- |
5,6,8,18,68–70 |
| Daily probability of death due to other causes General ward ICU |
0.01% 3% |
-- |
Expert consensus |
| Outpatient | |||
| Risk of developing MRSA infection per outpatient day among colonized patients <3 months 3–<6 months 6–<=12 months |
0.15% 0.09% 0.04% |
Triangular |
15,16 |
| Probability of requiring hospitalization if develop an outpatient MRSA infection |
47% |
Triangular |
15,16 |
*
Based on cost of skin and soft tissue infections
**
We 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.
***
We 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.