Table 4.
Pain intensity and activity interference at baseline and 4 and 12 months later, and estimated effects of opioid use prior to the 12-month assessment on 12-month pain intensity and activity interference (N = 1,157)
| Pain intensity | Activity Interference | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Opioid use, 120-day period prior to 12-mo interview | Pain intensity, baseline Adjusted M (95% CI) | Pain intensity, 4 mo Adjusted M (95% CI) | Pain intensity, 12 mo Adjusted M (95% CI) | Estimated effect of opioid use at 12 mo (95% CI)* | P-value** | Activity interference, baseline Adjusted M (95% CI) | Activity interference, 4 mo Adjusted M (95% CI) | Activity interference, 12 mo Adjusted M (95% CI) | Estimated effect of opioid use at 12 mo (95% CI)* | P-value** |
| Minimal/no | 5.96 (5.74, 6.18) | 5.26 (5.05, 5.47) | 4.91 (4.68, 5.13) | Ref | <0.001 | 5.67 (5.35, 5.99) | 4.53 (4.22, 4.83) | 3.77 (3.43, 4.11) | Ref | <0.001 |
| Intermittent/lower-dose | 6.05 (5.82, 6.29) | 5.83 (5.61, 6.04) | 5.71 (5.50, 5.92) | 0.80 (0.59, 1.10) | 5.51 (5.16, 5.87) | 4.97 (4.64, 5.30) | 4.61 (4.27, 4.95) | 0.84 (0.51, 1.17) | ||
| Regular/higher-dose | 6.12 (5.88, 6.35) | 5.82 (5.61, 6.03) | 5.72 (5.51, 5.93) | 0.81 (0.61, 1.02) | 5.43 (5.07, 5.78) | 4.99 (4.67, 5.30) | 4.84 (4.51, 5.18) | 1.08 (0.75, 1.40) | ||
Ref, reference group
Difference in the means between each opioid use group and the reference opioid use group (minimal/no use). The P-value for a two-sided t-test of the difference of the estimated effect (coefficient) from zero was <0.001 for each estimated effect shown in the table.
P-value for Wald test of any difference overall among the opioid use categories
Note: Estimated effects of opioid use were obtained from regression analyses that were adjusted for age; gender; disability status (permanently/temporarily disabled or not); confirmed opioid initiator status (yes, no); and baseline and 4-mo values of number of pain days in the past 6 mo; widespread pain bothersomeness; GAD-2; PHQ-8; pain intensity; and activity interference. The mean baseline pain intensity and activity interference scores shown in the table were adjusted for all of these variables except baseline pain intensity or activity interference, respectively. The 4- and 12-mo mean pain intensity and activity interference scores shown were adjusted for all of these variables.