Utility and quality-adjusted life year data
| Measure | All patients* | Patients with DLS who underwent decompression alone, and the matched patients with hip or knee OA† | Patients with DLS who underwent decompression with fusion, and the matched patients with hip or knee OA‡ | ||||||
|---|---|---|---|---|---|---|---|---|---|
| MIS decompression with or without fusion for DLS n = 66 | Primary THA for hip OA n = 66 | Primary TKA for knee OA n = 66 | MIS decompression for DLS n = 35 | Primary THA for hip OA n = 35 | Primary TKA for knee OA n = 35 | MIS decompression and fusion for DLS n = 31 | Primary THA for hip OA n = 31 | Primary TKA for knee OA n = 31 | |
| Baseline utility, mean ± SD | 0.578 ± 0.089 | 0.636 ± 0.116 | 0.657 ± 0.131 | 0.592 ± 0.079 | 0.640 ± 0.132 | 0.592 ± 0.079 | 0.562 ± 0.097 | 0.632 ± 0.096 | 0.664 ± 0.129 |
| Follow-up utility, mean ± SD | 0.705 ± 0.120 | 0.797 ± 0.142 | 0.770 ± 0.143 | 0.710 ± 0.126 | 0.789 ± 0.151 | 0.752 ± 0.141 | 0.699 ± 0.116 | 0.807 ± 0.132 | 0.791 ± 0.145 |
| Utility change, mean ± SD | 0.127 ± 0.134 | 0.161 ± 0.143 | 0.113 ± 0.132 | 0.118 ± 0.136 | 0.149 ± 0.157 | 0.101 ± 0.127 | 0.137 ± 0.134 | 0.175 ± 0.128 | 0.127 ± 0.138 |
| Lifetime QALY gain, mean ± SD§ | 1.948 ± 2.106 | 2.470 ± 2.298 | 1.784 ± 2.139 | 1.658 ± 1.842 | 2.102 ± 2.293 | 1.468 ± 1.987 | 2.276 ± 2.356 | 2.887 ± 2.268 | 2.142 ± 2.278 |
Note: ANOVA = analysis of variance; DLS = degenerative lumbar spondylolisthesis; MD = mean difference; MIS = minimally invasive surgery; OA = ostearthritis; QALY = quality-adjusted life year; SD = standard deviation; THA = total hip arthroplasty; TKA = total knee arthroplasty.
↵* Baseline utility was significantly lower (p < 0.003, ANOVA) for the DLS group than for the H-OA group (MD 0.058, p = 0.011) or the K-OA group (MD 0.079, p < 0.001). Follow-up utility was significantly lower (p < 0.004, ANOVA) for the DLS group than for the H-OA group (MD 0.093, p <0.001) or the K-OA group (MD 0.065, p = 0.018). There was no significant difference (p = 0.12, ANOVA) in utility gains between the groups. There was a significant utility gain at follow-up from baseline values for the DLS group (p < 0.001, paired t test), the H-OA group (p < 0.001, paired t test) and the K-OA group (p < 0.001, paired t test).
↵† There was no significant difference (p = 0.09, ANOVA) in baseline utility between the groups. There was no significant difference (p = 0.07, ANOVA) in follow-up utility between the groups. There was no significant difference (p = 0.36, ANOVA) in utility gains between the groups. There was a significant utility gain at follow-up from baseline values for the DLS group (p < 0.001, paired t test), the H-OA group (p < 0.001, paired t test) and the K-OA group (p < 0.001, paired t test).
↵‡ Baseline utility was significantly lower (p = 0.001, ANOVA) for the DLS group than for the H-OA group (MD 0.07, p = 0.039) or the K-OA group (MD 0.102, p = 0.001). Follow-up utility was significantly lower (p = 0.001, ANOVA) for the DLS group than for the H-OA group (MD 0.108; p = 0.005) or the K-OA group (MD 0.092; p = 0.022). There was no significant difference (p = 0.33, ANOVA) in utility gains between the groups. There was a significant utility gain at follow-up from baseline values for the DLS group (p < 0.001, paired t test), the H-OA group (p < 0.001, paired t test) and the K-OA group (p < 0.001, paired t test).
↵§ QALY gains were discounted at a 3% annualized rate.