Parameter Estimates from Regression Models of Postoperative Consumption of Morphine Equivalents (mg/kg/day) against Conditioned Pain Modulation, Situational Pain Catastrophizing, Anxiety, and Depression.

The effect of preoperative conditioned pain modulation and situational pain catastrophizing on patients' consumption of morphine equivalents following chest wall surgery. State anxiety and depression are solely included in the models to statistically control the effect of pain catastrophizing on postoperative morphine consumption (a priori confounders). The regression outputs indicate that conditioned pain modulation significantly predicted postoperative morphine consumption (Model 1). Situational pain catastrophizing was not related with postoperative movement-evoked pain (Models 2 and 3).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.