Table 1.
Input parameters used to estimate the number of outcomes averted by neuraminidase inhibitors (NAI) treatment and the cost per averted hospitalization
| Parameter | Value | Range (probability distribution) | Source |
|---|---|---|---|
| Total population | 62 280 000 | Fixed | 35 |
| Clinical attack rate (CAR) | |||
| 2009 pandemic | 7% | Fixed | Box A1, page 31 of Ref.46 |
| Transmissibility scenario 1 | 20% | Fixed | 28 |
| Transmissibility scenario 2 | 30% | Fixed | 28 |
| % Seeking outpatient care (non-high-risk)a | |||
| 2009 pandemic | 40% | 32–43% (Uniform) | 47 |
| Severity 1 | 60% | Fixed | 28 |
| Severity 2 | 70% | Fixed | 28 |
| % Seeking outpatient care (high-risk) | |||
| 2009 pandemic | 51.2% | 43.2–54.2% (Uniform) | Assumed from Ref.48 |
| Severity 1 | 71.2% | Fixed | Assumed in line with Ref.48,28 |
| Severity 2 | 81.2% | Fixed | Assumed in line with Ref.48,28 |
| % Of high-risk individuals | 30% | 27–33% (Uniform) | 49 |
| Case hospitalization risk (non-high-risk) | |||
| 2009 Pandemic | 0.30% | 0.27–0.33% (Uniform) | From Annex G, page 171 of Ref.50 |
| Severity 1 | 1.05% | Fixed | 28 |
| Severity 2 | 4.00% | Fixed | 28 |
| Case hospitalization risk (high-risk) | |||
| 2009 pandemic | 1.50% | 1.35–1.65% (Uniform) | Assumed from page 10 of Ref.29 that at-risk groups would have an increased risk of hospital admission by five times |
| Severity 1 | 5.25% | Fixed | Assumed in line with Refs.28,29 |
| Severity 2 | 20.00% | Fixed | Assumed in line with Refs.28,29 |
| % Of care-seeking patients prescribed NAI | 73% | 60–85% (Triangular) | 32 |
| Prescription of NAIs for non-influenza ILI as a % of those receiving NAIs for influenza | 40% | 30–50% (Uniform) | Assumed from Ref.31 |
| NAI (any time) compliance (as a %) | 64% | 55–70% (Uniform) | 32 |
| Effectiveness of NAI treatment (<48 h from symptom onset) on hospitalization (risk reduction) (Intention-to-treat-infected) |
63% | 83–19% (Triangular) | Assumed for pandemic influenza from Ref.19 |
| Mortality risk (in-hospital) | |||
| 2009 Pandemic | 5.3% | Fixed | 51 |
| Severity 1 | 5.3% | Fixed | Assumed to be fixed between scenarios |
| Severity 2 | 5.3% | Fixed | Assumed to be fixed between scenarios |
| Costs | |||
| Before being input into the model, all costs listed below were inflated to the 2017 UK Pound Sterling (£) (The hospital & community health services (HCHS) index) | |||
| Cost of GP consultation | £ 37 | 52,55 | |
| Cost of telephone consultation | £ 22 | 52,55 | |
| Average (weighted) outpatient consultation cost | £24.2 | £22–£37 (Truncated log normal) | |
| Cost of NAI (+delivery) | £ 16 | Fixed | 53 |
| High-risk patients: Cost of Hospitalization due to influenza (per patient) | £1727 | £1263–£2075 (Truncated log normal) | 54, 55 |
| Low-risk patients: Cost of Hospitalization due to influenza (per patient) | £436 | £307–£504 (Truncated log normal) | 54,55 |
aThis includes consultations made through the National Pandemic Flu Service (NPFS) telephone line.