Factors associated with opioid usage based on multivariable longitudinal mixed-effects logistic regression model (n = 706).
| Variables | Adjusted OR (95% CI) | p |
|---|---|---|
| Antidepressant usage (use vs no use) by muscle relaxants usage* | ||
| When muscle relaxants taken | 0.9 (0.3–2.9) | 0.85 |
| When muscle relaxants not taken | 2.2 (1.3 3.8) | 0.004 |
| PtGA ≥ 23 | 2.6 (1.5–4.6) | 0.0006 |
| CES-D total > 16 | 1.6 (1.1–2.3) | 0.02 |
| BASFI ≥ 40/100 mm | 1.9 (1.2–2.9) | 0.004 |
| BASDAI ≥ 4/10 cm | 2.0 (1.4–2.9) | 0.0005 |
| Exercise ≥ 3×/wk | 0.7 (0.5–1.1) | 0.13 |
| > 2 comorbidities | 1.2 (0.7–2.1) | 0.46 |
| Medication usage | ||
| Hypnotics | 5.4 (2.6–11.3) | < 0.0001 |
| Prednisone | 2.5 (1.4–4.7) | 0.003 |
| Anxiolytics | 4.0 (2.2–7.1) | < 0.0001 |
| TNFi agents | 0.7 (0.5–1.0) | 0.05 |
| NSAID | 1.1 (0.7–1.5) | 0.76 |
| DMARD | 1.3 (0.8–2.1) | 0.33 |
| Antipsychotics | 21.8 (0.4–8.4) | 0.32 |
| BASRI baseline ≥ 6** | 0.8 (0.5–1.4) | 0.41 |
| Elevated CRP | 1.5 (0.9–2.5) | 0.13 |
| Education (> gr 12) | 1.1 (0.5–2.2) | 0.84 |
| Marital status: married | 1.9 (1.1–3.2) | 0.02 |
| Race: white (compared to others) | 1.5 (0.7–2.9) | 0.29 |
| Male sex | 1.2 (0.7–2.2) | 0.48 |
| Age ≥ 40 yrs | 1.9 (0.7–3.4) | 0.03 |
| Smoking (> 100 packs within lifetime) | 1.8 (1.1–3.0) | 0.02 |
↵* OR for antidepressant usage were calculated separately by muscle relaxants usage (i.e., when muscle relaxants were taken or not taken) based on an interaction effect between muscle relaxants and antidepressant usage in the multivariable model.
↵** Because of a high correlation between BASRI and mSASSS and the greater completeness of the data in the former, it was decided to adjust BASRI instead of mSASSS in the final multivariable model. BASFI: Bath Ankylosing Spondylitis Functional Index; BASRI: Bath Ankylosing Spondylitis Radiological Index; CES-D: Center for Epidemiologic Studies Depression Scale; DMARD: disease-modifying antirheumatic drugs; mSASSS: modified Stokes Ankylosing Spondylitis Scoring System; NSAID: nonsteroidal antiinflammatory drugs; PtGA: patient’s global assessment; TNFi: tumor necrosis factor inhibitors; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; CRP: C-reactive protein.