Electrolyte abnormalities may increase mortality in patients with eating disorders

Electrolyte abnormalities within 1 year of eating disorder diagnosis are associated with an increased risk of all-cause mortality, a population-based study in Canada has shown.

“Patients with eating disorders are at a higher risk of electrolyte abnormalities than the general population,” wrote the researchers. “[Therefore,] we conducted the first representative cohort study to assess whether electrolyte abnormalities in patients with eating disorders are associated with mortality and physical health outcomes.” [Lancet Psychiatry 2024;11:818-827]

A total of 6,163 patients aged ≥13 years with an eating disorder and an electrolyte measure within 1 year since diagnosis (mean age, 26.8 years; female, 88.5 percent) in Ontario, Canada, were included.

Electrolyte abnormalities, which are defined as hypokalaemia, hyperkalaemia, hyponatraemia, hypernatraemia, hypomagnesaemia, hypophosphataemia, metabolic acidosis, or metabolic alkalosis, occurred in 32.2 percent of patients within 1 year of diagnosis of eating disorders. The most common electrolyte abnormalities were hypokalaemia (50.0 percent), hyponatraemia (37.8 percent), and hypernatraemia (21.1 percent).

Electrolyte abnormalities were associated with increased risks of all-cause mortality (15.7 vs 5.6 percent; hazard ratio [HR], 1.23; 95 percent confidence interval [CI], 1.03–1.48) and any hospitalization (60.5 vs 47.4 percent; HR, 1.35; 95 percent CI, 1.25–1.46) vs no electrolyte abnormality.

Electrolyte abnormalities were also associated with increased risks of multiple serious physical health conditions, including acute kidney injury (10.4 vs 3.0 percent; HR, 1.91; 95 percent CI, 1.50–2.43), chronic kidney disease (12.3 vs 4.3 percent; HR, 1.44; 95 percent CI, 1.17–1.77), bone fracture (7.0 vs 4.0 percent; HR, 1.40; 95 percent CI, 1.10–1.78), and bowel obstruction (3.6 vs 1.4 percent; HR, 1.62; 95 percent CI, 1.12–2.35) vs no electrolyte abnormality. However, electrolyte abnormalities were not associated with elevated risks of infection (88.8 vs 87.9 percent; HR, 0.99; 95 percent CI, 0.94–1.06) or cardiovascular event (8.6 vs 3.5 percent; HR, 1.04; 95 percent CI, 0.82–1.32).

“[Our] findings largely persisted when focusing on younger patients aged <25 years and those without previous history of these physical health conditions at baseline,” noted the researchers.

Consistent with previous studies from populations without an eating disorder, electrolyte abnormalities in adults who presented to the emergency department were also associated with increased morbidity and mortality. Notably, hyponatraemia and hypokalaemia were associated with 58 and 73 percent increased risk of in-hospital mortality, respectively. [PLoS One 2019;14:e021567]

“To our knowledge, this is the first study to assess and find that any electrolyte abnormality within 1 year of eating disorder diagnosis was associated with increased risk of mortality,” summarized the researchers. [Lancet Psychiatry 2024;11:818-827]

These results suggest that electrolyte abnormalities in patients with newly diagnosed eating disorders might be a direct or indirect marker of the severity of the eating disorder. Clinical vigilance, monitoring, and therapeutic intervention of electrolyte abnormalities and associated outcomes in patients with eating disorders may delay death and non-cardiovascular complications.