Table 3. Results of the Final Multivariable Logistic Regression Models for Transition From Acute to Chronic Low Back Pain for Those With Complete 6-Month Follow-Up and Adjusted by Inverse Probability Weighting.
| Factor | Complete 6-mo follow-up | Inverse probability weighteda | ||
|---|---|---|---|---|
| aOR (95% CI) | P value | aOR (95% CI) | P value | |
| Patient characteristics | ||||
| Race | ||||
| White | 1 [Reference] | .05 | 1 [Reference] | .17 |
| Black or African American | 1.31 (1.04-1.65) | 1.22 (0.98-1.52) | ||
| Other, declined, or not availableb | 1.25 (0.93-1.69) | 1.18 (0.89-1.55) | ||
| Health insurance | ||||
| Private insurance | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| Medicaid | 1.91 (1.53-2.38) | 1.88 (1.50-2.36) | ||
| Medicare | 1.43 (1.21-1.69) | 1.54 (1.30-1.82) | ||
| Workers’ compensation, self-pay, missing, or other | 1.05 (0.87-1.26) | 1.08 (0.90-1.29) | ||
| Body mass indexc | ||||
| Normal or underweight, <25 | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| Overweight, 25 to <30 | 1.12 (0.93-1.35) | 1.57 (1.31-1.87) | ||
| Obesity, ≥30 | 1.52 (1.28-1.80) | 1.53 (1.28-1.83) | ||
| Missing or unknown | 1.15 (0.82-1.62) | 1.24 (0.96-1.60) | ||
| Smoker | ||||
| Not current | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| Current | 1.56 (1.29-1.89) | 1.63 (1.35-1.97) | ||
| Not available | 1.10 (0.90-1.36) | 1.15 (0.93-1.41) | ||
| Clinical characteristics | ||||
| Presenting diagnosis | ||||
| Axial back pain | 1 [Reference] | .04 | 1 [Reference] | .03 |
| Back and leg pain | 1.16 (1.00-1.35) | 1.17 (1.01-1.36) | ||
| SBT risk level | ||||
| Low | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| Medium | 1.59 (1.33-1.89) | 1.63 (1.37-1.94) | ||
| High | 2.45 (2.00-2.98) | 2.52 (2.06-3.07) | ||
| Baseline Oswestry Disability Index score | ||||
| Minimal, 0-20 | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| Moderate, 21-40 | 1.16 (0.97-1.39) | 1.14 (0.95-1.37) | ||
| Severe, 41-60 | 1.82 (1.48-2.24) | 1.85 (1.50-2.28) | ||
| Very severe, ≥61 | 2.08 (1.60-2.68) | 1.83 (1.49-2.26) | ||
| Missing or unknown | 1.90 (1.29-2.80) | 1.66 (1.12-2.46) | ||
| Psychological comorbidities | ||||
| None | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| Depression/anxiety | 1.66 (1.28-2.15) | 1.73 (1.32-2.23) | ||
| Practice characteristics | ||||
| Geographic location | ||||
| UPMC | 1 [Reference] | .08 | 1 [Reference] | .01 |
| Intermountain Healthcare | 0.80 (0.64-0.99) | 0.80 (0.65-1.00) | ||
| Johns Hopkins Medicine | 0.86 (0.64-1.16) | 0.88 (0.67-1.16) | ||
| Boston Medical Center | 1.19 (0.89-1.59) | 1.35 (1.03-1.77) | ||
| Guideline recommended processes of care | ||||
| Nonconcordant composite | ||||
| 0 | 1 [Reference] | <.001 | 1 [Reference] | <.001 |
| 1 | 1.39 (1.21-2.32) | 1.41 (1.22-1.63) | ||
| 2 | 1.88 (1.53-2.32) | 1.90 (1.53-2.36) | ||
| 3 | 2.16 (1.10-4.25) | 2.03 (1.01-4.08) | ||
Abbreviations: aOR, adjusted odds ratio; SBT, Subgroups for Targeted Treatment Back tool; UPMC, University of Pittsburgh Medical Center.
a
The median (interquartile range) of the inverse probability weights equaled 0.94 (0.49-6.15).
b
Other included American Indian or Alaska Native, Asian, Hawaiian or Pacific Islander, and multirace.
c
Body mass index calculated as weight in kilograms divided by height in meters squared.