Table 4.
Results of multilevel model predicting pain ratings during conditioned pain modulation
| Estimates of Fixed Effects |
95% CI
|
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| Parameter | Estimate | SE | t-test | p-value | Lower | Upper |
|
| ||||||
| Intercept | 31.303 | 2.069 | 15.13 | 0.000 | 27.230 | 35.376 |
| Ethnicity | 0.512 | 1.086 | 0.471 | 0.638 | −1.627 | 2.650 |
| CPM Phase | −6.735 | 0.555 | −12.143 | <0.001 | −7.827 | −5.642 |
| Discrimination | −9.131 | 7.162 | −1.275 | 0.203 | −23.234 | 4.971 |
| CPM Phase x Ethnicity | −0.944 | 0.551 | −1.713 | 0.088 | −2.029 | 0.142 |
| CPM Phase x Discrimination | 1.806 | 3.087 | 0.585 | 0.559 | −4.275 | 7.888 |
| Ethnicity x Discrimination | −1.042 | 5.814 | −0.179 | 0.858 | −12.493 | 10.410 |
| CPM Phase x Ethnicity x Discrimination | 1.978 | 3.087 | 0.641 | 0.522 | −4.103 | 8.060 |
| Stimulus Intensity | 0.195 | 0.076 | 2.569 | 0.011 | 0.046 | 0.345 |
| Stimulus Number | 0.742 | 0.155 | 4.771 | <0.001 | 0.435 | 1.048 |
| Trauma Exposure | 0.506 | 0.670 | 0.756 | 0.450 | −0.813 | 1.826 |
| Sex | 0.493 | 0.978 | 0.504 | 0.615 | −1.434 | 2.419 |
| Education | 3.031 | 1.442 | 2.102 | 0.037 | 0.191 | 5.871 |
| Income | 0.599 | 0.513 | 1.167 | 0.244 | −0.412 | 1.610 |
| General Health Perception | −0.167 | 0.075 | −2.224 | 0.027 | −0.316 | −0.019 |
| Age | 0.024 | 0.174 | 0.138 | 0.890 | −0.319 | 0.367 |
| BMI | 0.134 | 0.254 | 0.525 | 0.600 | −0.367 | 0.634 |
| Stress | −0.099 | 0.236 | −0.418 | 0.676 | −0.563 | 0.366 |
| Psych Distress | 31.438 | 17.837 | 1.763 | 0.079 | −3.693 | 66.568 |
| Blood Pressure | −0.038 | 0.125 | −0.307 | 0.759 | −0.285 | 0.208 |
|
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| Estimates of Random Effects |
95% CI
|
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| Parameter | Estimate | SE | z-test | p-value | Lower | Upper |
|
| ||||||
| AR1 diagonal | 31.009 | 2.022 | 15.338 | <0.001 | 27.290 | 35.236 |
| AR1 rho | 0.383 | 0.039 | 9.698 | <0.001 | 0.303 | 0.457 |
| Intercept Variance | 248.385 | 25.618 | 9.696 | <0.001 | 202.925 | 304.031 |
| Intercept, StimNum Covariance | −8.135 | 2.832 | −2.873 | 0.004 | −13.686 | −2.585 |
| StimNum Variance | 4.462 | 0.541 | 8.241 | <0.001 | 3.518 | 5.660 |
| Intercept, CPM Phase Covariance | −46.265 | 10.267 | −4.506 | <0.001 | −66.388 | −26.143 |
| StimNum, CPM Phase Covariance | 1.358 | 1.378 | 0.985 | 0.325 | −1.344 | 4.059 |
| CPM Phase Variance | 53.884 | 6.893 | 7.817 | <0.001 | 41.934 | 69.238 |
Note: CPM=conditioned pain modulation; Phase=codes for modulation during the conditioning stimulus; AR=autoregressive; Bolded values are associated with significant estimates. Ethnicity was coded 0=non-Hispanic White, 1=Native American. Sex was coded 0=male, 1=female.