TABLE 3.
Summary of Secondary Outcomes Over Time for Permanently Implanted Patients
| Baseline | 3‐Month | 12‐Month | 24‐Month | |
|---|---|---|---|---|
| BPI | ||||
| N | 50 | 45 | 43 | 38 |
| Mean severity score (SD) | 6.8 (1.1) | 3.3 (2.0) | 3.1 (2.1) | 2.8 (2.6) |
| Mean change from baseline, severity score (SD, P value) | — | 3.5 (1.7, P < 0.001) | 3.6 (1.9, P < 0.001) | 3.9 (2.9, P < 0.001) |
| Mean interference score (SD) | 7.1 (1.6) | 3.5 (2.7) | 3.2 (2.6) | 2.7 (2.8) |
| Mean change from baseline, interference score (SD, P value) | — | 3.5 (2.6, P < 0.001) | 3.8 (2.8, P < 0.001) | 4.2 (3.0, P < 0.001) |
| EQ‐5D‐5L | ||||
| N | 50 | 45 | 43 | 38 |
| Mean EQ index score (SD) | 0.404 (0.215) | 0.637 (0.193) | 0.633 (0.223) | 0.645 (0.277) |
| Mean change from baseline, EQ index score (SD, P value) | — | 0.233 (0.245, P < 0.001) | 0.214 (0.213, P < 0.001) | 0.221 (0.288, P < 0.001) |
| Minimally important difference from baseline, EQ index score (≥ 0.074) % | — | 80.0 | 88.4 | 81.6 |
| Mean EQ Health VAS score (SD) | 53.3 (20.6) | 73.2 (16.9) | 71.4 (21.9) | 77.1 (21.1) |
| Mean change from baseline, EQ Health VAS (SD, P value) | — | 18.4 (25.1, P < 0.001) | 17.4 (26.8, P < 0.001) | 22.2 (31.4, P < 0.001) |
| ODI | ||||
| N | 50 | 44 | 43 | 38 |
| Mean ODI score (SD) | 52.3 (12.3) | 34.6 (13.7) | 31.2 (16.1) | 31.5 (20.7) |
| Mean change from baseline, ODI score (SD, P value) | — | 17.1 (11.9, P < 0.001) | 20.3 (13.9, P < 0.001) | 18.4 (20.3, P < 0.001) |
| Minimum detectable change from baseline, ODI (≥ 10%) % | — | 70.5 | 76.7 | 71.1 |
| PSQI | ||||
| N | 50 | 45 | 42 | 38 |
| Mean PSQI score (SD) | 12.0 (4.2) | 8.4 (4.4) | 8.6 (5.4) | 7.8 (5.0) |
| Mean change from baseline, PSQI global score (SD, P value) | — | 3.5 (4.6, P < 0.001) | 3.1 (4.5, P < 0.001) | 3.8 (5.0, P < 0.001) |
| Clinically meaningful change from baseline (reduction ≥ 3 from baseline) % | — | 64.4 | 52.4 | 57.9 |
P values resulting from paired t‐test that the mean change from baseline was significantly different from 0 with an alpha of 0.05.
Abbreviations: BPI, Brief Pain Inventory; EQ‐5D‐5L, EuroQOL instrument; ODI, Oswestry Disability Index; PSQI, Pittsburgh Sleep Quality Index; SD, standard deviation; VAS, visual analogue scale.