Fluid requirements for adult inpatients with medically compromised eating disorders: a scoping review

Aims: This review aimed to describe the current evidence on fluid requirements for adults with medically compromised eating disorders, with objectives to: (1) review study designs and aims, (2) describe participant characteristics, (3) identify modes of fluid delivery, and (4) examine fluid reporting methods and adverse events relating to fluid intake. Methods: This scoping review was conducted following the Joanna Briggs Institute's methodology. Three research databases (PubMed, CINAHL, Embase) were searched until 25 November 2024 for relevant studies. Research articles examining adult (aged ≥18 years), acutely unwell, hospitalised patients with eating disorders and that included information on fluid (requirements, provision, intake, output and/or restrictions) and any fluid-related outcomes were included. Screening of search results was conducted independently in duplicate. Results were synthesised narratively. Results: The search strategy yielded 1691 articles, and 13 studies (total n = 104 participants) were included. All studies were observational, including case report (n = 10 studies) and prospective study designs (n = 3 studies). No study specifically aimed to examine fluid requirements. Participants were predominantly female, and all had anorexia nervosa. Fluid was provided by multiple routes in most studies, and fluid reporting was inconsistent. Conclusions: Limited evidence is available with no studies specifically addressing fluid requirements for adults with medically compromised eating disorders. The results identify major gaps in the evidence, including no justification for fluid provision or restrictions applied, minimal explanation as to how fluid may have impacted clinical presentations, and no fluid measurements conducted in totality from all fluid provision routes. Future research should prioritise larger, well-designed cohort studies with detailed fluid information to assist with building the evidence base and thereby enhancing nutritional support for this vulnerable group.