Table 3.

Cost-effectiveness of IVIG for severe sepsis/septic shock using the best-fitting and alternative synthesis models of effectiveness evidence (see Table 2 for detailed specification of the models)

(Best-fitting model, M1) Fixed-effect model estimate (IVIG/IVIGAM compared with albumin) considering 3 days duration of IVIG therapy				Probability of being cost-effective for cost-effectiveness threshold
Treatment	Mean cost	Mean QALY	ICER	£20,000/QALY	£30,000/QALY
IVIG	£54,901	4.35	£20,850	0.505	0.789
Standard care	£45,593	3.90		0.495	0.211
(Alternative model M2) Random-effects model estimate (IVIG/IVIGAM compared with albumin)
Treatment	Mean cost	Mean QALY	ICER	£20,000/QALY	£30,000/QALY
IVIG	£57,200	4.62	£16,177	0.597	0.707
Standard care	£45,593	3.90		0.403	0,295
(Alternative model M3) Random-effects model (IVIG/IVIGAM compared with albumin/no treatments) considering Jadad score = 5
Treatment	Mean cost	Mean QALY	ICER	£20,000/QALY	£30,000/QALY
IVIG	£55,238	4.39	£19,968	0.502	0.611
Standard care	£45,593	3.90		0.498	0.389
(Alternative model M4a) Random-effects model (IVIG/IVIGAM compared with albumin/no treatment) considering a sample size of 339
Treatment	Mean cost	Mean QALY	ICER	£20,000/QALY	£30,000/QALY
IVIG	£53,518	4.18	£28,520	0.404	0.514
Standard care	£45,593	3.90		0.596	0.486
(Alternative model M4b) Random-effects model (IVIG/IVIGAM compared with albumin/no treatment) considering a sample size of infinity
Treatment	Mean cost	Mean QALY	ICER	£20,000/QALY	£30,000/QALY
IVIG	£50,024	3.76	Dominated	0.275	0.348
Standard care	£45,593	3.90		0.725	0.652

IVIG, intravenous immunoglobulin; IVIGAM, immunoglobulin M-enriched polyclonal IVIG; QALY, quality-adjusted life years; ICER, incremental cost-effectiveness ratio.