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

FactorComplete 6-mo follow-upInverse probability weighteda
aOR (95% CI)P valueaOR (95% CI)P value
Patient characteristics
Race
White1 [Reference].051 [Reference].17
Black or African American1.31 (1.04-1.65)1.22 (0.98-1.52)
Other, declined, or not availableb1.25 (0.93-1.69)1.18 (0.89-1.55)
Health insurance
Private insurance1 [Reference]<.0011 [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 other1.05 (0.87-1.26)1.08 (0.90-1.29)
Body mass indexc
Normal or underweight, <251 [Reference]<.0011 [Reference]<.001
Overweight, 25 to <301.12 (0.93-1.35)1.57 (1.31-1.87)
Obesity, ≥301.52 (1.28-1.80)1.53 (1.28-1.83)
Missing or unknown1.15 (0.82-1.62)1.24 (0.96-1.60)
Smoker
Not current1 [Reference]<.0011 [Reference]<.001
Current1.56 (1.29-1.89)1.63 (1.35-1.97)
Not available1.10 (0.90-1.36)1.15 (0.93-1.41)
Clinical characteristics
Presenting diagnosis
Axial back pain1 [Reference].041 [Reference].03
Back and leg pain1.16 (1.00-1.35)1.17 (1.01-1.36)
SBT risk level
Low1 [Reference]<.0011 [Reference]<.001
Medium1.59 (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, 0-201 [Reference]<.0011 [Reference]<.001
Moderate, 21-401.16 (0.97-1.39)1.14 (0.95-1.37)
Severe, 41-601.82 (1.48-2.24)1.85 (1.50-2.28)
Very severe, ≥612.08 (1.60-2.68)1.83 (1.49-2.26)
Missing or unknown1.90 (1.29-2.80)1.66 (1.12-2.46)
Psychological comorbidities
None1 [Reference]<.0011 [Reference]<.001
Depression/anxiety1.66 (1.28-2.15)1.73 (1.32-2.23)
Practice characteristics
Geographic location
UPMC1 [Reference].081 [Reference].01
Intermountain Healthcare0.80 (0.64-0.99)0.80 (0.65-1.00)
Johns Hopkins Medicine0.86 (0.64-1.16)0.88 (0.67-1.16)
Boston Medical Center1.19 (0.89-1.59)1.35 (1.03-1.77)
Guideline recommended processes of care
Nonconcordant composite
01 [Reference]<.0011 [Reference]<.001
11.39 (1.21-2.32)1.41 (1.22-1.63)
21.88 (1.53-2.32)1.90 (1.53-2.36)
32.16 (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.

aThe median (interquartile range) of the inverse probability weights equaled 0.94 (0.49-6.15).

bOther included American Indian or Alaska Native, Asian, Hawaiian or Pacific Islander, and multirace. cBody mass index calculated as weight in kilograms divided by height in meters squared.