Table 1. Model inputs.
| Base-case value | Range of sensitivity analysis | References | |
| Clinical inputs | |||
| Prevalence of influenza infections in admitted patients with suspected influenza | 11% | 0.1%–30% | [25] |
| Proportion of 2009 H1N1 influenza infections in admitted patients with influenza A infection | 58% | 0%–97% | [25] |
| Proportion of patients with influenza infections presented within 48 hours of onset | 50% | 0–100% | [14] |
| Susceptibility of influenza A viruses to oseltamivir | 100% | 99.3%–100% | [26]–[27] |
| ICU admission rate | |||
| Seasonal influenza with late or no antiviral treatment | 10.5% | 3.1%–16.4% | [4], [14], [35] |
| Odds ratio with early antiviral treatment | 0.93 | 0.46–1.8 | [14] |
| 2009 H1N1 influenza with late or no antiviral treatment | 11.4% | 10.5%–12.2% | [4], [36] |
| Odds ratio with early antiviral treatment | 0.68 | 0.47–0.99 | [36] |
| Morality rate | |||
| Seasonal influenza with late or no antiviral treatment | 4.9% | 2.4%–10% | [4], [8], [14] |
| Odds ratio with early antiviral treatment | 0.20 | 0.06–0.80 | [8]–[9], [14] |
| 2009 H1N1 influenza with late or no antiviral treatment | 10% | 2.2%–22.8% | [4]–[7], [10]–[11] |
| Odds ratio with early antiviral treatment | 0.26 | 0.08–0.63 | [10]–[11] |
| Sensitivity of diagnostic test | |||
| IFA for seasonal influenza | 79.2% | 70%–85% | [16]–[17] |
| IFA for 2009 H1N1 influenza | 50% | 25%–75% | [18] |
| PCR for seasonal influenza | 99% | 98%–100% | [19]–[21] |
| PCR for 2009 H1N1 influenza | 98% | 86%–100% | [22]–[23] |
| Clinical judgment on influenza | 44% | 25%–75% | [37] |
| Specificity of diagnostic test | |||
| IFA for influenza | 99% | 80%–100% | [16]–[17] |
| PCR for l influenza | 97% | 89%–100% | [19]–[21] |
| Clinical judgment on influenza | 57% | 25%–75% | [37] |
| Utility Inputs | |||
| Utility score | |||
| 18–64 years | 0.92 | - | [28] |
| 65–85 years | 0.84 | - | [28] |
| Mean age of patients hospitalized with seasonal influenza | 70 | 18–80 | [35], [38] |
| Mean age of patients hospitalized with 2009 H1N1 influenza | 47 | 18–70 | [5], [10] |
| Cost Inputs (USD)* | |||
| Oseltamivir (per day) | 6 | 5–9 | - |
| Duration of oseltamivir treatment (days) | 5 | 5–10 | [39] |
| PCR | 25 | 20–30 | Expert opinion |
| IFA | 10 | 5–10 | Expert opinion |
| Hospitalization of influenza with no ICU care | 7,957 | 17,955–26,932 | [30] |
| Adjusting factor for cost of hospitalization with ICU care | 5 | 4–6 | - |
*
1 USD = 7.8 HK.