This study examined electrolytes associated with RS and found that rates of hypophosphatemia, hypokalemia, and/or hypomagnesemia were low despite the absence of prophylactic electrolyte supplementation. Though supplementation was more common among participants < 70% TGW, findings suggest that even in these lowest-weight patients, assertive nutritional advancement may be safely undertaken in the inpatient setting with vigilant watchful waiting and informed decision-making regarding electrolyte monitoring and management.

Standard practice for electrolyte management in early refeeding of hospitalized patients with RED has not been established [15]. Concern for RS typically arises based on review of an electrolyte panel alongside physical assessment [13, 15]. Universal supplementation prevents clear assessment of an individual’s physiologic function in a time of metabolic transition. Indeed, the majority of study patients with electrolyte derangements corrected without intervention, which suggests that watchful waiting—as opposed to reflexive or prophylactic supplementation—may be appropriate for hospitalized patients with severe malnutrition.

Our study had several limitations. First, the sample size was small, presenting a challenge to data analysis by smaller sub-groups (e.g. age), though our focus on severely malnourished inpatients addresses a notable gap in the existing literature. Second, although dietary management was generally consistent with an established protocol, data were collected over several years during which the protocol’s caloric starting point and advance were increased to reflect adjustments in standards of care [1]; this prevented application of universal caloric metrics. Similarly, supplementation was not implemented systematically or in a randomized fashion due to pragmatics in the clinical context (i.e., multiple factors needing to be considered/further assessed to determine supplementation), thus outcomes could not be definitively linked to supplementation status. Third, sociodemographic descriptors were limited by data in the EMR, including binary gender terms and broad characterization of race/ethnicity. Fourth, several participants were admitted multiple times, which may have introduced confounds related to severity or duration of illness; however, repeat admissions are part of the reality of inpatient eating disorder care and therefore important to consider in examination of RS in this setting. Finally, hypophosphatemia, hypokalemia, and/or hypomagnesemia in RED cannot always be attributed to RS; other potential reasons for electrolyte disturbance (e.g., purging) might present confounding factors.

Inpatient providers routinely contend with refeeding risks without a clear definition of RS [17] or standard electrolyte management guidelines. By comprehensively examining electrolytes during refeeding without use of prophylactic supplementation, this study might contribute to future guidelines on how to best manage RS risk in vulnerable individuals.