Table 1. . Model parameters.
| Parameter |
IMI/REL |
PIP/TAZ |
Source |
Ref. |
|---|---|---|---|---|
| Clinical parameters | ||||
|
Susceptibility
| ||||
| Susceptibility coverage |
93.8% |
86.0% |
SMART (US, 2017–19) |
[12] |
|
Clinical efficacy
| ||||
| Clinical response at Day 28 (MITT) |
51.9% |
50.6% |
RESTORE-IMI 2 |
[11] |
| All-cause mortality through Day 28 (MITT) |
15.9% |
21.3% |
||
| Subsequent CMS+IMI response rate |
40.0% |
|
RESTORE-IMI 1 |
[14] |
| Subsequent CMS+IMI mortality rate |
30.0% |
|
||
| Response odds ratio (switch due to nonsusceptibility) |
4.55 |
|
Raman et al. (2015) |
[8] |
| Mortality odds ratio (switch due to nonsusceptibility) |
2.92 |
|
Siempos et al. (2010) |
[15] |
|
Hospital LOS
| ||||
| Proportion of time intubated |
84.0% |
78.2% |
RESTORE-IMI 2 |
[11] |
| Average ICU LOS days - cured |
14.60 |
13.70 |
||
| Average ICU LOS days - uncured |
19.20 |
22.50 |
||
| Average ICU LOS days - death |
11.70 |
11.90 |
||
| Average general ward LOS days - cured |
5.30 |
6.10 |
||
| Average general ward LOS days - uncured |
3.80 |
2.10 |
||
| Average general ward LOS days - death |
0.20 |
0.20 |
||
| Additional LOS days due to nonsusceptibility |
6.50 |
|
Prabhu et al. (2015) |
[13] |
|
Adverse events
| ||||
| Thrombocytopenia |
0.38% |
0.00% |
RESTORE-IMI 2 |
[11] |
| Diarrhoea |
0.00% |
0.37% |
||
| Alanine aminotransferase increased |
0.75% |
0.00% |
||
| Aspartate aminotransferase increased |
0.75% |
0.00% |
||
| Generalised tonic-clonic seizure |
0.00% |
0.37% |
||
| Nephrotoxicity |
10.4% |
- |
RESTORE-IMI 1 | [14] |
| Subsequent CMS+IMI nephrotoxicity | 56.25% | |||
| Economic parameters | ||||
|---|---|---|---|---|
|
Drug costs
| ||||
| Treatment duration (days) – IMI/REL |
8.7 |
|
RESTORE-IMI 2 |
[11] |
| Treatment duration (days) – PIP/TAZ |
8.3 |
|
||
| Subsequent CMS+IMI treatment duration (days) |
6.1 |
|
RESTORE-IMI 1 |
[14] |
| IMI/REL – 500 mg/250 mg – 25 vials |
$6,687.50 |
|
NDC Code: 00006-3856-02 |
[17] |
| PIP/TAZ – 2 g/250 mg - 10 vials |
$30.00 |
|
NDC Code: 63323-0981-53 |
[17] |
| PIP/TAZ – 3 g/375 mg - 10 vials |
$30.00 |
|
NDC Code: 63323-0983-53 |
[17] |
| PIP/TAZ – 4 g/500 mg - 10 vials |
$56.10 |
|
NDC Code: 72572-0574-10 |
[17] |
| PIP/TAZ – 12 g/1500 mg - 1 vial |
$39.00 |
|
NDC Code: 61990-0140-01 |
[17] |
| PIP/TAZ – 36 g/4500 mg - 1 vial |
$65.00 |
|
NDC Code: 65219-0256-24 |
[17] |
|
Resource use costs
| ||||
| ICU cost on mechanical ventilator day 1 |
$19,800.90 |
|
Dasta et al. (2005), inflation adjusted to 2021. |
[18,21] |
| ICU cost on mechanical ventilator day 2 |
$8,797.95 |
|
||
| ICU cost on mechanical ventilator day 3+ |
$7,279.04 |
|
||
| ICU cost off mechanical ventilator day 1 |
$12,230.18 |
|
||
| ICU cost off mechanical ventilator day 2 |
$6,413.19 |
|
||
| ICU cost off mechanical ventilator day 3+ |
$5,837.17 |
|
||
| General ward unit cost per day |
$2,720.60 |
|
Kaiser Family Foundation (2018), inflation adjusted to 2021 |
[19,21] |
| Outpatient visit |
$183.19 |
|
2020 CMS Physician Fee Schedule |
[22] |
|
Adverse event costs
| ||||
| Thrombocytopenia |
$17,208.03 |
|
Healthcare Cost and Utilization Project (2017), inflation adjusted to 2021. |
[20,21] |
| Diarrhoea |
$6,936.34 |
|
||
| Alanine aminotransferase increased |
$8,684.18 |
|
||
| Aspartate aminotransferase increased |
$8,684.18 |
|
||
| Generalised tonic-clonic seizure |
$7,770.73 |
|
||
| Nephrotoxicity |
$14,051.62 |
|
||
|
Health-related quality of life
| ||||
| Utility value – ICU |
0.68 |
|
Whittington et al. (2017) |
[23] |
| Utility value – general ward | 0.73 | Lee et al. (2010) | [24] | |
CMS: Centers for Medicare and Medicaid Services; CMS+IMI: Colistin plus imipenem/cilastatin; ICU: Intensive care unit; IMI/REL: Imipenem/cilastatin/relebactam; LOS: Length of stay; MITT: Modified intent-to-treat; NDC: Nation Drug Code; PIP/TAZ: Piperacillin/tazobactam; SMART: Study for Monitoring Antimicrobial Resistance Trends.