Feasibility
Principal findings of this study were a consent rate of 85%, a fidelity rate of 62% and an attrition rate of 34%. Within 12 weeks, we recruited and successfully randomised 42 participants for the pilot study, i.e. 21 per arm. The participants accepted randomisation. One participant revoked his consent to participate in the study after assignment to the control group; the designated procedures to remove participant’s data worked. Some components of the intervention (e.g. self-help groups) could not be carried out largely due to COVID-19, which resulted in the 62% fidelity rate. Loss to follow-up mainly resulted from the fact that the participants were not (any longer) reachable. We know of three deceased participants during our study period. Data from other studies on ICU aftercare indicate that e.g. one-year-mortality is between 16–77% [We were able to deliver the intervention to 14/21 study participants in the ICU follow-up clinic (see Fig. At baseline, 27% study participants needed support to point their value on the EQ-5D-VAS at that time. Further, 85% of the participants needed help in filling out the follow-up questionnaires, which would mean high effort for a larger study. Those consisted of five measurement instruments (SF-12, PHQ, PTSS-10, Barthel index, health care use), which may explain the high amount of assistance needed. We did not carry out a detailed analysis of the feasibility or acceptance of the single measurement instruments used. However, in the interest of data economy, minimising the amount of missing values and reducing the burden on patients, we suggest that the selection and composition of the measurement instruments in the large-scale study should be chosen even more carefully. Choice of outcome measurement instruments for a future trial should consider recent developments, in particular regarding core outcome sets [