Cost effectiveness of antimicrobial catheters in the intensive care unit: addressing uncertainty in the decision

Table 1 Parameter estimates used in the model

Parameters		Baseline estimate	Variation (SEM)	Distribution	Source	Level of evidence
Infection-related events:
Probability of CR-BSI		Modeled in stepwise increments^a		Beta	Database	1
RR mortality (CR-BSI)		1.06	0.18	Log normal	[1]	2
Extra days in the ICU		2.41	0.83	Log normal	[22]	2
Extra days on hospital ward		7.54	1.81	Log normal
Effectiveness A-CVCs (RR):
SPC		0.54	0.62	Log transformed normal	[21]	1 +
CH/SSD (ext)		0.66	0.17
CH/SSD (int/ext)		0.70	0.43
MR		0.39	0.43
Baseline probabilities of mortality:
ICU mortality		0.098	0.002	Beta	Dataset	2
Hospital mortality		0.069	0.001	Beta	Dataset	2
Annual mortality post discharge	Year 1	0.050	0.002	Beta	[24]	2
	Years 2 to 3	0.027	0.002
	Years 4 to 5	0.028	0.002
	Years 6 to 10	0.037	0.003
	Years 11 to 15	0.042	0.003
Underlying annual mortality	45 to 64 years	0.004	-	NA	[25]	1
	65 to 84 years	0.030	-
	85 + years	0.140	-
Utilities:
Utility ICU		0.66	0.27	Beta	[28]	3
Utilities population norms	50 to 59 years	0.80	0.22	Beta	[27]	3
	60 to 69 years	0.79	0.19
	70 to 79 years	0.75	0.25
	80 + years	0.66	0.29
Costs, 2006 AUD:
ICU bed day		3,021	-	NA	[31]	4
Hospital bed day		843	-	NA	[32]	3
Diagnostics CR-BSI		101.70	-	NA	Database	1
Treatment CR-BSI		591.30	-	NA	Database	1
Additional cost per catheter	SPC	22.36	-	NA	Database	1
	CH/SSD (ext)	11.64	-
	CH/SSD (int/ext)	41.35	-
	MR	59.36	-

^aAvailable on request from the authors.
A-CVCs, antimicrobial central venous catheters; CH/SSD, chlorhexidine silver sulfadiazine; CR-BSI, catheter related bloodstream infection; ICU, intensive care unit; int/ext, internally and externally coated; MR, minocycline and rifampicin; RR, relative risk; SPC, silver, platinum and carbon.

ISSN: 1364-8535