Study design and setting
For this study, we used data from a pragmatic randomized controlled trial (RCT). The research question of this RCT was whether a telephone follow-up call reduces unplanned hospitalizations and URVs within 30 days of ED discharge, compared to a satisfaction survey call. The trial was conducted in the EDs of Haaglanden Medical Center (HMC), a non-academic teaching hospital in the Netherlands, from February 1, 2018 to July 1, 2019. In this RCT, 3175 patients were allocated to either the intervention (