Mapping length of inpatient treatment duration and year-wise relapse rates in eating disordered populations in a well-defined Western-European healthcare region across 1998-2020

Objectives: Updated international guideline recommendations for AN inpatient care rely on expert opinions/observational evidence and promote extended inpatient stays, warranting investigation using higher-level ecological evidence.

Methods: The study was conducted according to Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Data encompassing 13,885 ED inpatients (5336 adolescents and 8549 adults) was retrieved from Swedish public health registries. Variables analyzed included (1) ED inpatient care opportunities, (2) unique number of ED inpatients and (3) mean length of ED-related inpatient stays in age groups 15-19 and 20-88+, across 1998-2020.

Results: Mean length of inpatient stays was inversely correlated to relapse to ED-related inpatient care within the same year (p < 0.001, R-squared_adj = 0.5216 and p < 0.00001, R-squared_adj = 0.5090, in the 15-19 and 20-88+ age groups, respectively), independent of number of ED inpatients treated within a year in both age groups. Extending mean adolescent inpatient duration from 35 to 45 days was associated with a ∼30% reduction in the year-wise relapse rate.

Conclusions: Mean length of ED-related inpatient treatment stays was associated with reduced relapses to inpatient care within the same year, which could be interpreted as support for recommendations to include a stabilization phase in inpatient ED treatment.