Table 5.

Estimates of the mean incremental cost, incremental effect (QALY gain or OR) and cost-effectiveness of craniotomy compared with DC in the base case and two sensitivity analyses (based on imputed data)

Cost-utility analysis	Incremental cost (95% CI) (N=126)	QALY gain (95% CI) (N=122)	ICER	CEAC*
Base-case: imputed	−£5520 (−£18 060 to £7020)	0.093 (0.029 to 0.156)	Dominant	87%
SA wider cost perspective	−£17 793 (−34 658 to −928)	0.094 (0.030 to 0.159)	Dominant	99%
SA lowest EQ-5D-5L baseline score	−£5445 (−£17 547 to £6658)	0.089 (0.025 to 0.152)	Dominant	87%

Cost-effectiveness analysis	Incremental cost (95% CI)	OR (95% CI)†	ICER
Base case	−£4536 (−£17 374 to £8301)	1.682 (0.995 to 2.842)	Dominant	–
SA wider cost perspective	−£16 900 (−£33 807 to £7)	1.693 (0.998 to 2.871)	Dominant	–

*Probability of being cost-effective on the CEAC at a threshold of £20 000 per QALY.

†For a favourable outcome for craniotomy compared with DC, based on the Extended Glasgow Outcome Scale, as described in the Methods section.

CEAC, cost-effectiveness acceptability curve; 95% CI, 95% confidence interval; DC, decompressive craniectomy; Dominant, lower mean costs and higher mean effect; EQ-5D-5L, EuroQoL 5-Dimension 5-Level; ICER, incremental cost-effectiveness ratio; N, number allocated to that trial arm and included in the analysis – imputation was undertaken as part of all presented analyses; QALY, quality-adjusted life-years; SA, sensitivity analysis.