Table 2.
Five-year cost-effectiveness of new test strategies versus current test strategy
| Test strategy | New test | Sea | Spa | Test costsa | TP n (%) | FP n (%) | TN n (%) | FN n (%) | Costs | QALYs | ∆Costs | ∆QALYs | ICER | Headroomb |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ACR/EULAR 2010 RA | 0.62 | 0.77 | €1,593d | 185 (34) | 58 (11) | 195 (35) | 114 (21) | €16,784 | 3.430 | |||||
| Add-on all patients | B-cell | 0.60 | 0.90 | €150 | 254 (46) | 77 (14) | 175 (32) | 46 (8) | €16,807 | 3.454 | €23 | 0.024 | €969 | €602 |
| IL-6 | 0.70 | 0.53 | €50 | 265 (48) | 149 (27) | 103 (19) | 34 (6) | €17,387 | 3.451 | €603 | 0.021 | €28,171 | -€125e | |
| MRI | 0.90 | 0.60 | €756 | 288 (52) | 135 (24) | 117 (21) | 11 (2) | €17,848 | 3.461 | €1,063 | 0.031 | €34,318 | €312 | |
| Genetic | 0.40 | 0.85 | €750 | 231 (42) | 87 (16) | 166 (30) | 69 (13) | €17,611 | 3.444 | €827 | 0.014 | €57,606 | €210 | |
| Add-on intermediate-risk patients | B-cell | 0.60 | 0.90 | €150 | 244 (44) | 74 (13) | 178 (32) | 56 (10) | €16,748 | 3.450 | -€37 | 0.020 | Dominantc | €511 |
| IL-6 | 0.70 | 0.53 | €50 | 254 (46) | 135 (24) | 117 (21) | 46 (8) | €17,271 | 3.448 | €487 | 0.018 | €26,696 | -€72e | |
| MRI | 0.90 | 0.60 | €756 | 273 (49) | 124 (22) | 128 (23) | 27 (5) | €17,404 | 3.456 | €620 | 0.026 | €23,457 | €269 | |
| Genetic | 0.40 | 0.85 | €750 | 224 (41) | 82 (15) | 170 (31) | 75 (14) | €17,211 | 3.442 | €427 | 0.012 | €35,233 | €173 | |
| Example of what would happen if one would replace the RA classification criteria | ||||||||||||||
| Replacement all | B-cell | 0.60 | 0.90 | €150 | 180 (33) | 25 (5) | 227 (41) | 120 (22) | €15,983 | 3.432 | -€801 | 0.002 | Dominantc | €984 |
| IL-6 | 0.70 | 0.53 | €50 | 210 (38) | 119 (22) | 134 (24) | 90 (16) | €16,849 | 3.434 | €64 | 0.004 | €17,526 | €59 | |
| MRI | 0.90 | 0.60 | €756 | 270 (49) | 101 (18) | 151 (27) | 30 (5) | €17,139 | 3.458 | €355 | 0.027 | €12,906 | €951 | |
| Genetic | 0.40 | 0.85 | €750 | 120 (22) | 38 (7) | 214 (39) | 180 (33) | €16,675 | 3.414 | € -110 | -0.016 | €6,914 | €543 | |
Se sensitivity, Sp specificity, TP true positive, FP false positive, TN true negative, FN false negative, QALY quality-adjusted life year, ICER incremental cost-effectiveness ratio (€ per QALY gained), ACR/EULAR American College of Rheumatology/European League Against Rheumatism, RA rheumatoid arthritis, MRI magnetic resonance imaging. aThese are the Se, Sp and costs of the new test; the Se and Sp of the combination of the new test plus the ACR/EULAR criteria are reported in the text. bWillingness to pay threshold is €20,000 per QALY gained. cDominant = better health outcomes and lower costs. dCosts of visits and diagnostic tests during first year. eMainly due to the low specificity, an IL-6 test as an add-on can never be cost-effective compared to the current test strategy