Table 2.
Baseline characteristics.
| NSAID/APAP user | NSAID/APAP nonuser | |||
|---|---|---|---|---|
| Duloxetine N = 137 | Placebo N = 82 | Duloxetine N = 206 | Placebo N = 156 | |
| Age in years, mean (SD) | 53.1 (14.7) | 51.4 (13.3) | 53.5 (14.9) | 53.1 (13.6) |
| Female, n (%) | 89 (65.0) | 52 (63.4) | 114 (55.3) | 85 (54.5) |
| Ethnicity, n (%) | ||||
| African American | 3 (2.2) | 3 (3.7) | 19 (9.2) | 13 (8.3) |
| Caucasian | 108 (78.8) | 61 (74.4) | 160 (77.7) | 123 (78.9) |
| East Asian | 0 | 0 | 2 (1.0) | 3 (1.9) |
| Hispanic | 25 (18.3) | 17 (20.7) | 22 (10.7) | 15 (9.6) |
| Native American | 0 | 0 | 1 (0.5) | 2 (1.3) |
| West Asian | 1 (0.7) | 1 (1.2) | 2 (1.0) | 0 |
| CLBP duration since onset, years, mean (SD) | 11.4 (11.5) | 9.2 (9.1) | 10.8 (11.1) | 10.3 (9.0) |
| QT F class 1, n (%) | 94 (72.9) | 63 (79.8) | 150 (75.4) | 99 (68.3) |
| BPI average pain, mean (SD) | 6.1 (1.6) | 6.0 (1.6) | 5.9 (1.6) | 6.1 (1.7) |
| RMDQ-24, mean (SD) | 9.6 (5.0) | 8.6 (4.8) | 9.1 (4.5) | 9.8 (5.3) |
There was a statistically significant difference in RMDQ-24 scores between treatments in the nonuser subgroup, but this difference was not considered clinically significant.
Abbreviations: APAP, acetaminophen; BPI, Brief Pain Inventory; CLBP, chronic low back pain; NSAID, nonsteroidal anti-inflammatory drugs; QTF, Quebec Task Force; RMDQ-24, Roland-Morris Disability Questionnaire, SD, standard deviation.