Statistical analysis
SECONDARY, SENSITIVITY
Analyses were conducted by a statistician (BH) blinded to group allocation of clusters. All analyses were cluster-adjusted following the intention-to-treat principle.Baseline characteristics were displayed descriptively. The primary outcome (PAM-13) was compared between intervention and control group using a linear mixed model and adjusted for baseline value (fixed effect) and random (cluster) effects. An additional baseline adjusted linear mixed model was fitted to investigate the course of the primary outcome in both time points t1 and t2. This model includes time and interaction time × group as additional fixed effects and was further adjusted for repeated measurement (covariance pattern structure general). For patients, who terminated the study early, imputation was performed using last observation carried forward (LOCF). Sensitivity analyses were conducted as complete case analysis without last observation carried forward. The same analytic approach was used for secondary endpoints. The binary secondary outcomes were aggregated as percentages on cluster level, and ordinary linear models were fitted. On cluster level these models are by itself cluster adjusted and differences of percentages can easily be estimated from the model.Statistical tests were performed two-sided at a significance level of α = 0.05 and 95% CI were estimated.All statistical analyses were conducted with SAS for Windows version 9.4 (SAS Institute Inc, Cary, North Carolina).