Table 1.
Characteristics by responder status
| Variable | Overall cohort* | Responder*† | Non-responder*† | P value‡ |
| Sample size, n | 40 | 23 | 17 | – |
| Mean age (SD) in years | 67.9 (12.9) | 67.8 (12.2) | 68.0 (14.3) | 0.97 |
| Sex, n (%) | ||||
| Female | 18 (45.0) | 10 (43.5) | 8 (47.0) | 1.00 |
| Male | 22 (55.0) | 13 (56.5) | 9 (53.0) | |
| Body mass index (SD) in kg/m2 | 31.3 (5.7) | 31.7 (4.2) | 31.0 (7.4) | 0.67 |
| Current tobacco use, n (%) | 10 (25.0) | 5 (21.7) | 5 (29.4) | 0.72 |
| Opioid use, n (%) | 17 (42.5) | 8 (34.8) | 9 (53.0) | 0.34 |
| Daily OME (SD) in mg | 13.2 (22.3) | 8.8 (18.1) | 15.0 (25.6) | 0.38 |
| Neuropathic medication use, n (%) | 20 (50.0) | 14 (60.9) | 6 (35.3) | 0.20 |
| Preimplant NRS pain score (SD) | 8.3 (1.4) | 8.2 (1.5) | 8.4 (1.0) | 0.75 |
| Preholiday NRS pain score (SD) | 7.3 (1.7) | 7.0 (1.7) | 7.7 (1.5) | 0.18 |
| Time from implant to holiday (SD) in days | 452.7 (326.4) | 451.1 (277.7) | 453.4 (355.9) | 0.98 |
| Length of holiday (SD) in days | 17.3 (20.6) | 13.0 (8.4) | 20.5 (27.3) | 0.23 |
| Type of waveform after holiday, n (%) | ||||
| 10 kHz | 34 (85.0) | 22 (95.6) | 12 (70.6) | 0.07 |
| Tonic/10 kHz combination | 6 (15.0) | 1 (4.3) | 5 (29.4) | |
| Pain diagnosis, n (%) | ||||
| FBSS | 26 (65.0) | 12 (52.2) | 14 (82.4) | 0.09 |
| NSRBP | 9 (22.5) | 7 (30.4) | 2 (11.8) | 0.26 |
| PDN | 2 (5.0) | 2 (8.7) | 0 (0) | 0.50 |
| Radiculopathy | 2 (5.0) | 1 (4.3) | 1 (5.9) | 1.00 |
| Peripheral neuropathy | 1 (2.5) | 1 (4.3) | 0 (0) | 1.00 |
Baseline characteristics are reported at the time of stimulation holiday initiation.
Comparisons were made using independent t-test for continuous outcomes and Fisher’s exact test for categorical outcomes.
*Mean±SD presented for continuous outcomes and frequency with percentage presented for categorical outcomes.
†Responder status denotes ≥50% relief in pain intensity after stimulation holiday, whereas non-responder status denotes <50% relief in pain intensity after stimulation holiday.
‡Independent sample t-tests used to compare means and Fisher’s exact test used to compare proportions between responders and non-responders.
FBSS, failed back surgery syndrome; NRS, Numeric Rating Scale; NSRBP, non-surgical refractory back pain; OME, oral morphine equivalent; PDN, painful diabetic neuropathy.