Hester van Eeren

Subgroup analysis using the propensity score | 4 71 | Figure 1. Boxplots of the overlap of the univariate propensity score (PS) distributions Circle is a mild outlier (defined when the value > 3rd quartile + 1.5 • interquartile range or < 1st quartile - 1.5 • interquartile range). Aterisk is an extreme outlier (defined when the value > 3rd quartile + 3 • interquartile range or < 1st quartile - 3 • interquartile range). Table 3. Linear regression on GSI outcome Variables (N=727) B 95% CI Standardized coefficient Using the univariate PS Intercept 0.512** 0.408 – 0.614 - Long duration treatment group 0.106* 0.006 – 0.206 0.092 Severe problems 0.366** 0.168 – 0.564 0.240 Interaction -0.147 -0.382 – 0.088 -0.084 Using the generalized PS Intercept 0.536** 0.426 - 0.646 - Short duration – mild problems Reference - - Short duration – severe problems 0.348** 0.091 – 0.605 0.129 Long duration – mild problems 0.113* 0.011 – 0.215 0.099 Long duration – severe problems 0.244** 0.064 – 0.424 0.139 *p<0.05. **p<0.01. CI indicate confidence interval; GSI, Global Severity Index; PS, propensity score.