TABLE 3.
Patients' Characteristics Divided by Two Distinct Clusters
| Missing | Total | Cluster 1 | Cluster 2 | P-value | |
|---|---|---|---|---|---|
| M | 151 | 79 | 72 | ||
| Responder, n (%) | 62 | 29 (36.7%) | 33 (45.8%) | .331 | |
| High responder, n (%) | 31 (20.5) | 14 (17.7) | 17 (23.6) | .488 | |
| Age, y, mean (SD) | 0 | 54.8 (12.0) | 51.5 (11.8) | 58.5 (11.2) | <.001 |
| Sex, n (%) | |||||
| Female | 0 | 84 (55.6) | 48 (60.8) | 36 (50.0) | .244 |
| Male | 67 (44.4) | 31 (39.2) | 36 (50.0) | ||
| BMI, mean (SD) | 0 | 32.2 (7.6) | 32.3 (7.7) | 32.0 (7.6) | .838 |
| Pain duration, mean (SD) | 3 | 47.8 (17.5) | 43.8 (19.4) | 52.3 (13.8) | .002 |
| Pelvis_Baseline, n (%) | 52 (34.4) | 29 (36.7) | 23 (31.9) | .657 | |
| Back_Baseline, n (%) | 91 (60.3) | 46 (58.2) | 45 (62.5) | .712 | |
| Neck_Baseline, n (%) | 28 (18.5) | 12 (15.2) | 16 (22.2) | .368 | |
| Legs_Baseline, n (%) | 106 (70.2) | 57 (72.2) | 49 (68.1) | .710 | |
| Arms_Baseline, n (%) | 34 (22.5) | 18 (22.8) | 16 (22.2) | .911 | |
| Diagnosis (%) | |||||
| FBSS | 78 (51.7) | 34 (43.0) | 44 (61.1) | .04 | |
| CRPS | 24 (15.9) | 19 (24.1) | 5 (6.9) | .008 | |
| Neuropathy | 18 (11.9) | 8 (10.1) | 10 (13.9) | .645 | |
| Others | 31 (20.5) | 18 (22.8) | 13 (18.1) | .605 | |
| Psychiatric family history, n (%) | |||||
| None | 0 | 142 (94.0) | 74 (93.7) | 68 (94.4) | 1.000 |
| Yes | 9 (6.0) | 5 (6.3) | 4 (5.6) | ||
| Anxiety, n (%) | |||||
| None | 0 | 115 (76.2) | 58 (73.4) | 57 (79.2) | .534 |
| Mild | 32 (21.2) | 18 (22.8) | 14 (19.4) | ||
| Moderate | 2 (1.3) | 2 (2.5) | |||
| Severe | 2 (1.3) | 1 (1.3) | 1 (1.4) | ||
| Depression, n (%) | |||||
| None | 0 | 97 (64.2) | 48 (60.8) | 49 (68.1) | .361 |
| Mild | 49 (32.5) | 27 (34.2) | 22 (30.6) | ||
| Moderate | 3 (2.0) | 3 (3.8) | |||
| Severe | 2 (1.3) | 1 (1.3) | 1 (1.4) | ||
| Smoking (%) | |||||
| Never smoking | 67 (44.4) | 38 (48.1) | 29 (40.3) | ||
| Former smoking | 43 (28.5) | 16 (20.3) | 27 (37.5) | .030 | |
| Current smoking | 41 (27.2) | 25 (31.6) | 16 (22.2) | ||
| Insurance (%) | |||||
| Medicare | 3 (2.0) | 3 (4.2) | .106 | ||
| Commercial | 110 (72.8) | 56 (70.9) | 54 (75.0) | .701 | |
| No-fault | 5 (3.3) | 3 (3.8) | 2 (2.8) | 1 | |
| Workers' compensation | 33 (21.9) | 20 (25.3) | 13 (18.1) | .378 | |
| Previous spinal surgeries (SD) | 0 | 1.3 (1.6) | 0.9 (1.2) | 1.6 (1.8) | .005 |
| Months from previous surgerya (SD) | 0 | 80.6 (101) | 66.1 (75.8) | 92.9 (117.5) | .22 |
| NRS Baseline, mean (SD) | 0 | 6.9 (1.7) | 7.9 (1.3) | 5.8 (1.4) | <.001 |
| ODI_Baseline, mean (SD) | 10 | 25.2 (7.2) | 27.5 (6.3) | 22.6 (7.4) | <.001 |
| BDI_Baseline, mean (SD) | 21 | 13.3 (9.0) | 17.0 (9.6) | 9.6 (6.6) | <.001 |
| PCSTotal_Baseline, mean (SD) | 17 | 23.2 (12.9) | 32.0 (9.7) | 14.1 (8.7) | <.001 |
| MPQTotal_Baseline, mean (SD) | 0 | 5.2 (2.8) | 5.6 (2.9) | 4.8 (2.6) | .048 |
| MPQAffective_Baseline, mean (SD) | 0 | 0.7 (0.9) | 0.8 (1.0) | 0.6 (0.9) | .167 |
BDI, Beck's depression inventory; BMI, body mass index; CRPS, complex regional pain syndrome; FBSS, failed back surgery syndrome; MPQ, McGill pain questionnaire; NRS, numeric rating scale; ODI, Oswestry disability index; PCS, pain catastrophizing scale; SD, standard deviation.
a
Only including patients with at least 1 previous surgery.
N = Sample size.
The statistically significant differences are highlighted in bold.