Table. Parameters used in the model to assess the cost-effectiveness of target HTLV-1 antenatal screening in England and Wales.
| Parameter | Point estimate | Lower limit | Upper limit | Reference |
|---|---|---|---|---|
| Risk factors for transmission | ||||
| HTLV-1 prevalence in pregnant women from high prevalence areas | 0.006 | 0.004 | 0.008 | [12] |
| Prevalence of breastfeeding | 0.960 | 0.864 | 1.000 | [19] |
| Probability of breastfeeding for 6 months or more | 0.610 | 0.549 | 0.671 | [19] |
| Performance of diagnostic tests | ||||
| Sensitivity of ELISA | 0.999 | 0.978 | 0.999 | [18] |
| Specificity of ELISA | 0.995 | 0.991 | 0.999 | [18] |
| Sensitivity of Western blot | 0.971 | 0.923 | 0.999 | [18] |
| Specificity of Western blot | 0.925 | 0.860 | 0.975 | [18] |
| Probability of HTLV-1 transmission | ||||
| Probability of HTLV-1 mother-to-child transmission if breastfeeding lasts for < 6 months | 0.058 | 0.046 | 0.070 | [18] |
| Probability of HTLV-1 mother-to-child transmission if breastfeeding lasts for ≥ 6 months | 0.175 | 0.140 | 0.210 | [18] |
| Probability of residual HTLV-1 mother-to-child transmission without breastfeeding | 0.025 | 0.020 | 0.050 | [18] |
| Costs in GBP (EUR) | ||||
| Cost of ELISA (individually) | GPB 1.40 (EUR 1.63) |
GBP 1.26 (EUR 1.46) |
GBP 1.54 (EUR 1.79) |
Product quote |
| Cost of Western blot (individually) | GBP 19.75 (EUR 22.94) |
GBP 17.77 (EUR 20.64) |
GBP 21.72 (EUR 25.22) |
Product quote |
| Cost of breastfeeding interruption (cabergoline and formula) (per individual) | GBP 730.95 (EUR 848.86) |
GBP 657.85 (EUR 763.97) |
GBP 804.04 (EUR 933.74) |
Estimated according to Methods |
| Cost of asymptomatic HTLV-1 infection (per individual/per year) | GBP 2,900 (EUR 3,367.80) |
GBP 2,610 (EUR 3,031.02) |
GBP 3,190 (EUR 3704.59) |
Imperial College Healthcare NHS Trust Resource Group |
| Cost of HAM (per individual/per year) | GBP 16,000 (EUR 18,580.99) |
GBP 14,400 (EUR 16,722.89) |
GBP 17,600 (EUR 20,439.09) |
Imperial College Healthcare NHS Trust Resource Group |
| Cost of ATL (per individual/year) | GBP 16,739.00 (EUR 19,439.20) |
GBP 15,065.10 (EUR 17,490.64) |
GBP 18,412.90 (EUR 21,383.12) |
Imperial College Healthcare NHS Trust Resource Group |
| Risk of disease | ||||
| Relative risk of death of people living with HTLV-1 vs those without | 1.570 | 1.370 | 1.800 | [18] |
| Hazard ratio of death for people with HAM vs those without | 5.030 | 1.959 | 12.911 | [18] |
| Probability of death in people with ATL | 0.2943 | 0.2713 | 0.3183 | [18] |
| Probability of developing HAM | 0.0053 | 0.0026 | 0.0109 | [18] |
| Probability of developing ATL | 0.0010 | 0.0006 | 0.0015 | [18] |
| Probability of progression to ATL for people living with HAM | 0.0038 | 0.0030 | 0.0046 | [18] |
| Utility value | ||||
| Utility value of asymptomatic infection | 0.780 | 0.702 | 0.858 | [36] |
| Utility value of ATL | 0.262 | 0.182 | 0.288 | [18] |
| Utility value of HAM | 0.203 | 0.182 | 0.223 | [36] |
| Utility value without HTLV-1 infection | 0.910 | 0.819 | 1.000 | [36] |
| Discount rate | 0.03 | NA | NA | [20] |
ATL: adult T-cell leukaemia; ELISA: enzyme-linked immunoassay; HAM: HTLV-1-associated myelopathy; HTLV-1: human T-cell lymphotropic virus type 1; NA: not applicable.
ELISA was used as an initial screening and Western blot as confirmatory test for HTLV-1 infection. All costs are reported in pound sterling (GBP) and Euros (GBP 1 = EUR 1.16, conversion date: 9 Apr 2024).