Base-case model parameters
| Parameter | Value | Distribution | Source |
| Tranexamic acid risk ratio treatment effect | |||
| Head injury | 0.78 | Log normal (μ=−0.248, σ=0.1) | CRASH-3 trial8 |
| Non-head injury | 1 | N/A | CRASH-3 trial8 |
| 28 risk of death | |||
| Head injury death (UK) | 0.061 | Beta (α=42, β=643) | CRASH-3 trial8 |
| Head injury death (Pakistan) | 0.079 | Beta (α=165, β=1919) | CRASH-3 trial8 |
| Non-head injury death (UK) | 0.018 | Beta (α=12, β=673) | CRASH-3 trial8 |
| Non-head injury death (Pakistan) | 0.005 | Beta (α=11, β=2073) | CRASH-3 trial8 |
| Long-term standardised mortality ratios | |||
| First year, postinjury | 4.00 | Normal (95% CI 3.27 to 4.90) | McMillan12 |
| Beyond first year, postinjury | 2.26 | Normal (95% CI 1.84 to 2.77) | McMillan12 |
| Utility | |||
| Good recovery | 0.894 | Beta (α=50, β=5.9) | Ward Fuller15 |
| Moderate disability | 0.675 | Beta (α=30.5, β=14.7) | Ward Fuller15 |
| Severe disability | 0.382 | Beta (α=10.9, β=17.7) | Ward Fuller15 |
| Vegetative state | −0.178 | Beta (α=16.1, β=−106.3) | Ward Fuller15 |
| Average utility (weighted average of above disabilities)* | 0.75 | By component (based on above distributions for disabilities)ˆ | Calculated |
| Costs (UK) | |||
| Tranexamic acid (full dose) | £6.00 | N/A | BNF18 |
| Sodium chloride | £3.25 | N/A | BNF18 |
| Needle and syringe | £0.05 | N/A | NICE20 |
| Hospital cost | £4741 | Gamma (k=31.4, θ=0.43)† | NHS Reference costs23/CRASH-3 trial8 |
| Monitoring costs (first year post, injury) | £11 662 | By component (see online supplementary materials) | Beecham et al
25 / Lecky et al 26 |
| Monitoring costs (after first year, postinjury) | £2505 | By component (see online supplementary materials) | Lecky et al 26/expert opinion |
| Costs (Pakistan) | |||
| Tranexamic acid (full dose) | US$1.92 | N/A | Drug information system19 |
| Sodium chloride | US$0.46 | N/A | Drug information system19 |
| Needle and syringe | US$0.20 | N/A | Dziekan et al 21 |
| Hospital cost | US$92 | Gamma (k=21.8, θ=0.34)† | WHO CHOICE24/CRASH-3 trial8 |
| Monitoring costs | US$0 | N/A | Expert opinion |
*Deterministic and probabilistic average utility values are estimated from a weighted average of CRASH-3 patients with good recovery (3094), moderate disability (1288), severe disability (677) and vegetative state (124).
†Gamma distribution for hospital length of stay (UK: 13.7 days, Pakistan: 7.4 days).
BNF, British National Formulary; N/A, not available; NHS, National Health Service; NICE, National Institute for Health and Care Excellence.