As a first step, the Berlin FBT team analysed previously published international data [Haas et al., 2022]. This study indicated that FBT could achieve similar results to inpatient treatment in terms of weight improvements in children and adolescents with AN - and with significantly fewer and shorter hospital stays. However, this analysis is not directly transferable to the German healthcare system, as there were differences in the groups studied across countries, such as age, initial weight, or severity of the disease.
The second step involved a comparison of routine treatment data from Berlin (IMT group) and the USA (FBT group) [Nadler et al., 2022]. After adjusting the data for differences such as age and initial weight, the weight gain was comparable in both groups. However, participants in the FBT group spent significantly less time in hospital (on average 3 days compared to 121 days in the IMT group). Nevertheless, these results should be viewed with caution as the samples were small and some important clinical data were missing (e.g. on thoughts and actions that constitute and maintain AN, psychological distress from the eating disorder, and the duration of inpatient treatment was not known for all participants in the FBT group).
As a result, a pilot study on FBT was conducted at the Charité in Berlin [Haas et al., 2024]. In this study, 31 patients who usually would have received inpatient treatment were treated by specially trained FBT therapists. This group was compared with a similar group receiving standard inpatient treatment at the Charité in Berlin. The result: both groups showed comparable improvements in weight and eating disorder-specific symptoms. Importantly, the hospitalisation time in the FBT group was significantly shorter (median 1 day compared to 121 days in the IMT group). However, the number of participating families was small (31 per group) and the study was conducted at only one centre. In addition, there was no randomisation (i.e. no random allocation to the form of therapy), which significantly limits the strength of this pilot study.
The FIAT study is being conducted with a design similar to the pilot study, but with a more methodologically sophisticated and therefore more robust design, and a much larger patient group. The study is designed to investigate the same underlying question in a larger number of families and across more clinics: can FBTSCM help as many patients as IMT? At the same time, the training of therapists for their participation in the FIAT study will significantly expand the pool of professionals trained in FBT for the further treatment of patients with AN beyond the end of the study.