Table 1
Input parameters for model (parameters that were estimated by expert panel are in italics)
| Parameter | Value | Source | Range for sensitivity analysis |
|---|---|---|---|
| *Refers to the first two years of disease. | |||
| †Disease after two years of continued exposure. | |||
| NPV, net present value; YNHH, Yale New Haven Hospital. | |||
| Clinical parameters: | |||
| Sensitisation rate | 2.8%/year | Petsonk et al23 | 0.7%/year21 to 5.3%/year23 |
| Time to diagnosis | |||
| 1. No surveillance | 2.7 years after onset of symptoms | Tarlo et al10 | 18 months42 – 5.9 years10 |
| 2. With surveillance | 1.7 years after onset of symptoms | Tarlo et al10 | 6 months43 – 2.7 years |
| Disease progression | |||
| 1. Exposed | 2 years | Expert panel | 1–10 years |
| 2. Removed | 51% remain symptomatic | Extrapolated from Pisati et al7 | 0–50% at 48 months recovered8 |
| Chance of removal | |||
| 1. If patients diagnosed | 71% of workers removed at 6 months | Ross and McDonald12 | 15% at 11 years44 – 99% removed at 6 months |
| 2. Undiagnosed patients | 24% change job within 1 year | Blanc et al41 | 0 to same rate as 1 |
| Chance of recovery, if removed | |||
| 1. More reversible* | At 5 years, 28% of removed patients recovered | Pisati et al7 | 50% at 4 years8 – 18% at 10 years45 |
| 2. Less reversible† | 14% at 5 years | Extrapolated from Pisati et al7 | |
| Likelihood of disability | |||
| 1. Removed | 30% disabled at 4 years | Ross and McDonald12 | 0–69% at 4.1 years45 |
| 2. Still exposed | 60% disabled at 4 years | Expert panel | |
| Cost parameters: | |||
| Lost productivity | |||
| 1. Employer perspective | $0 | None | None |
| 2. Societal perspective | NPV of 28% income loss × 10 years on $50,000/year | Moscato et al28 and industry profile27 | 28%–56%28 |
| Diagnosis costs | |||
| 1. Screening cost | $103.88 | Charges YNHH, with cost:charge ratio of 0.45 | 50% to 200% |
| 2. Confirmation | $453.53 | ||
| Medical/absenteeism costs | |||
| 1. Symptomatic state | $42.62/month | Birnbaum et al,29 and calculations from model | 50–200% |
| 2. Chronic state | $85.24/month | As for 1 | As for 1 |
| 3. Disabled state | $1513.60/month | As for 1 | As for 1 |
| Discount rate | 3% | US Panel16 | 0–7%16 |
