Differences in pooled mean costs and effects (95% CIs), incremental cost-effectiveness (CE) ratios, and the distribution of incremental cost-effect pairs around the quadrants of the cost-effectiveness planes for PTED compared with usual care
| Sample size | Outcome measure | ∆C (95% CI) | ∆e (95% CI) | ICER | Distribution CE-plane (%) | |||||
| PTED | OM | € | Points | €/point | NE | SE | SW | NW | ||
| Main analysis—imputed dataset | 179 | 309 | Leg pain (range: 0–100, lower is better) | −2786 (−4399 to −1181) | 6.9* (1.3 to 12.6) | −402 Dominant | 0.1 | 99.4 | 0.5 | 0 |
| 179 | 309 | QALYs (range: 0–1) | −2825 (−4400 to −1222) | 0.040 (0.007 to 0.074) | −70235 Dominant | 0.1 | 99.2 | 0.7 | 0 | |
| SA1—unadjusted outcomes | 179 | 309 | Leg pain (range: 0–100, lower is better) | −2543 (−4380 to −686) | 8.2* (2.5 to 13.9) | −310 Dominant | 0.6 | 99.2 | 0.1 | 0 |
| 179 | 309 | QALYs (range: 0–1) | −2543 (−4380 to −686) | 0.052 (0.016 to 0.088) | −48496 Dominant | 0.6 | 99.2 | 0.2 | 0 | |
| SA2—complete cases† | 130 | 183 | Leg pain (range: 0–100, lower is better) | −2083 (−3991 to −234) | 7.8* (1.5 to 14.0) | −267 Dominant | 1.5 | 98 | 0.5 | 0 |
| 130 | 183 | QALYs (range: 0–1) | −2133 (−4029 to −280) | 0.031 (−0.008 to 0.070) | −68014 Dominant | 1 | 93.3 | 5.4 | 0.3 | |
| SA3a—cost of PTED=5000 | 179 | 309 | Leg pain (range: 0–100, lower is better) | −2260 (−3876 to −650) | 6.9* (1.3 to 12.6) | −326 Dominant | 0.6 | 98.9 | 0.5 | 0 |
| 179 | 309 | QALYs (range: 0–1) | −2300 (−3916 to −693) | 0.040 (0.007 to 0.074) | −57167 Dominant | 0.5 | 98.8 | 0.7 | 0 | |
| SA3b—cost of PTED=Cost of OM | 179 | 309 | Leg pain (range: 0–100, lower is better) | −3212 (−4824 to −1610) | 6.9* (1.3 to 12.6) | −464 Dominant | 0 | 99.5 | 0.5 | 0 |
| 179 | 309 | QALYs (range: 0–1) | −3251 (−4863 to −1651) | 0.040 (0.007 to 0.074) | −80820 Dominant | 0 | 99.3 | 0.7 | 0 | |
| SA4—human capital approach | 179 | 309 | Leg pain (range: 0–100, lower is better) | −4111 (−6384 to −1919) | 6.9* (1.3 to 12.5) | −594 Dominant | 0 | 99.5 | 0.5 | 0 |
| 179 | 309 | QALYs (range: 0–1) | −4179 (−6466 to −1983) | 0.040 (0.007 to 0.074) | −103256 Dominant | 0 | 99.3 | 0.7 | 0 | |
| SA5—healthcare perspective | 179 | 309 | Leg pain (range: 0–100, lower is better) | −144 (−724 to 406) | 6.9* (1.3 to 12.6) | −21 Dominant | 30.3 | 69.3 | 0.2 | 0.3 |
| 179 | 309 | QALYs (range: 0–1) | −152 (−731 to 398) | 0.040 (0.007 to 0.074) | −3773 Dominant | 29.2 | 70.1 | 0.3 | 0.5 | |
| SA6 —including learning curve patients | 304 | 309 | Leg pain (range: 0–100, lower is better) | −2573 (−3995 to −1192) | 5.4 (0.7 to 10.1) | −476 Dominant | 0 | 98.9 | 1 | 0 |
| 304 | 309 | QALYs (range: 0–1) | −2602 (−4028 to −1226) | 0.040 (0.012 to 0.068) | −65097 Dominant | 0 .0 | 99.7 | 0.3 | 0 | |
Please note that the difference in total societal costs of this table slightly differs from that of table 2. This is given by the fact that in the current table, a system of seemingly unrelated regressions was used for estimating cost differences, whereas linear regression was used for table 2.
*The difference measures improvement in leg pain symptoms; that is, positive number signalises a decrease in symptoms.
†Variable indicating preference for treatment was left out because it was constant in some of the bootstrapped samples.
ICER, incremental cost-effectiveness ratios; NE, north east; NW, north west; PTED, percutaneous transforaminal endoscopic discectomy; QALYs, quality-adjusted life years; SE, south east; SW, south west.