Parameter Estimates from Regression Models of Postoperative Movement-evoked Pain Intensity (NRS 0–10) against Preoperative Conditioned Pain Modulation, Situational Pain Catastrophizing, Anxiety, and Depression.

The effect of preoperative conditioned pain modulation and situational pain catastrophizing on patients' ratings of movement-evoked pain intensity following chest wall surgery. State anxiety and depression are solely included in the models to statistically control the effect of pain catastrophizing on postoperative pain (a priori confounders). The regression outputs indicate that situational pain catastrophizing significantly predicted postoperative movement-evoked pain intensity, per se (Model 2), and independently of anxiety and depression (Model 3). The adjusted R-squared values indicate that up to 23% of variance in the dependent variable (postoperative movement-evoked pain) can be explained by the independent variable Log[S-PCS]. Conditioned pain modulation was not related with postoperative movement-evoked pain (Model 1).
N  =  the number of observations used in the regression analysis; 95% CI  = 95% confidence interval for the coefficients; P value  =  two-tailed P values used in testing the null hypothesis that the coefficient (parameter) is 0 using an alpha of 0.05; CPM%  =  conditioned pain modulation (i.e., relative difference between pressure pain thresholds obtained before and after 120 s cold pressor test); Log[S-PCS]  =  Situational Pain Catastrophizing Scale score (log-transformed); STAI  =  Spielberger's State Anxiety and Inventory score; BDI  =  Beck's Depression Inventory score; F-statistic  =  the mean square model divided by the mean square residual. The P value associated with the F-statistic is used in testing the null hypothesis that all of the model coefficients are 0; Adj. R-squared  =  a modified version of R-squared that has been adjusted for the number of predictors in the model.