Table 3. Results of partially-adjusted regression models for modifiable variables (15% expenditure percentile criterion)a.
| Variable | Reference classification | Risk ratiob,c | 95% CI | |
|---|---|---|---|---|
| Lower | Upper | |||
| BMI | Low | 0.99 | 0.98 | 1.02 |
| Medium | 0.99 | 0.98 | 1.02 | |
| Smoking status (Yes vs No) | Low | 1.28 | 0.88 | 1.83 |
| Medium | 1.34 | 0.97 | 1.86 | |
| Missed work days in Year 1 (missed ≥1-day vs no missed days) | Low | 3.75* | 2.33 | 5.99 |
| Medium | 2.15* | 1.46 | 3.17 | |
| PCS | Low | 0.94* | 0.92 | 0.95 |
| Medium | 0.95* | 0.94 | 0.96 | |
| MCS | Low | 0.97* | 0.96 | 0.98 |
| Medium | 0.97* | 0.96 | 0.98 | |
| Pain interference (Moderate, quite a bit or extreme vs a little bit or none) | Low | 5.10* | 3.76 | 6.94 |
| Medium | 3.16* | 2.44 | 4.08 | |
| General psychological distress | Low | 1.09* | 1.06 | 1.11 |
| Medium | 1.08* | 1.05 | 1.10 | |
| Depression | Low | 1.29* | 1.19 | 1.39 |
| Medium | 1.23* | 1.15 | 1.31 | |
| Perceived health status (Fair or poor vs good, very good or excellent) | Low | 2.11* | 1.55 | 2.89 |
| Medium | 2.19* | 1.67 | 2.87 | |
| Perceived mental health status (Fair or poor vs good, very good or excellent) | Low | 1.72* | 1.15 | 2.56 |
| Medium | 1.35 | 0.96 | 1.90 | |
| Ability to overcome (Disagree strongly, somewhat or uncertain vs agree somewhat or strongly) | Low | 1.52 | 0.90 | 2.57 |
| Medium | 1.54 | 0.96 | 2.47 | |
| Usual care provider (Yes vs No) | Low | 1.60 | 0.91 | 2.79 |
| Medium | 1.51 | 0.88 | 2.59 | |
| Total prescription medications in Year 1 | Low | 1.46* | 1.36 | 1.57 |
| Medium | 1.22* | 1.16 | 1.28 | |
a Parameters are for partially-adjusted models where each variable was considered individually after accounting for non-modifiable variables: age, sex, race, ethnicity, years of education, poverty category, employment status, metropolitan statistical area, census region, insurance status, number of comorbidities, diagnosis type and total number of musculoskeletal pain diagnoses.
b Risk ratios were adjusted for non-modifiable variables and reflect relative risk of being classified as HIGH compared to the reference classification. For continuous variables, values represent relative risk of being classified as HIGH compared to the reference classification for every one unit increase in the variable.
c Asterisk indicates p<0.05
Low = annual pain-related expenditures in the lowest 15%; Medium = annual pain-related expenditures between 15–85%; PCS = physical component subscale of the SF-12, MCS = mental component subscale of the SF-12.