Baseline Characteristics of Study Participants by Treatment Groupa
| No. (%) | ||||
|---|---|---|---|---|
| Control | LTOT | |||
| Characteristic | (n = 201) | (n = 201) | P | SDiffb |
| Age (years) | ||||
| 21 to 49 | 59 (29.4) | 57 (28.4) | ||
| 50 to 64 | 101 (50.2) | 90 (44.8) | 0.29 | 0.05 |
| 65 to 79 | 41 (20.4) | 54 (26.9) | ||
| Gender | ||||
| Man | 54 (26.9) | 51 (25.4) | 0.73 | 0.03 |
| Woman | 147 (73.1) | 150 (74.6) | ||
| Race | ||||
| White | 152 (75.6) | 159 (79.1) | ||
| Black | 39 (19.4) | 38 (18.9) | 0.25 | 0.05 |
| Other | 10 (5.0) | 4 (2.0) | ||
| Duration of low back pain (years) | ||||
| ≤5 | 51 (25.4) | 48 (23.9) | 0.73 | 0.03 |
| >5 | 150 (74.6) | 153 (76.1) | ||
| Pain catastrophizing | ||||
| 0 to 17 | 94 (46.8) | 94 (46.8) | ||
| 18 to 34 | 68 (33.8) | 68 (33.8) | >0.99 | 0.00 |
| 35 to 52 | 39 (19.4) | 39 (19.4) | ||
| Pain self-efficacy | ||||
| 0 to 20 | 46 (22.9) | 59 (29.4) | ||
| 21 to 40 | 89 (44.3) | 91 (45.3) | 0.17 | 0.07 |
| 41 to 60 | 66 (32.8) | 51 (25.4) | ||
| Chronic widespread pain | ||||
| No | 137 (68.2) | 141 (70.1) | 0.67 | 0.04 |
| Yes | 64 (31.8) | 60 (29.9) | ||
| Ever had work loss ≥1 month due to low back pain | ||||
| No | 103 (51.2) | 105 (52.2) | 0.84 | 0.02 |
| Yes | 98 (48.8) | 96 (47.8) | ||
| Ever received disability or workers' compensation benefits due to low back pain | ||||
| No | 146 (72.6) | 144 (71.6) | 0.82 | 0.02 |
| Yes | 55 (27.4) | 57 (28.4) | ||
| Ever filed a law suit or legal claim due to low back pain | ||||
| No | 182 (90.5) | 183 (91.0) | 0.86 | 0.02 |
| Yes | 19 (9.5) | 18 (9.0) | ||
| Prior low back surgery | ||||
| No | 159 (79.1) | 156 (77.6) | 0.72 | 0.04 |
| Yes | 42 (20.9) | 45 (22.4) | ||
| Health-related quality of life, mean (SD) | 58.01 (7.16) | 58.71 (6.36) | 0.30 | 0.10 |
| Low back pain intensity, mean (SD) | 6.39 (1.67) | 6.39 (1.92) | 0.98 | 0.00 |
| Back-related disability, mean (SD) | 15.32 (5.49) | 15.41 (5.23) | 0.87 | 0.02 |
| Pain impact, mean (SD) | 32.57 (8.75) | 32.88 (8.24) | 0.72 | 0.04 |
Abbreviation: LTOT, long-term opioid therapy.
Notes: aTreatment groups were matched on propensity score using a logistic regression model that included all variables in the table, with a caliper width of .001. Health-related quality of life involved a composite measure of anxiety, depression, fatigue, sleep disturbance, and pain interference. Higher values represented worse quality of life.
bMagnitude of the standardized difference.