What accounts for the high mortality of anorexia nervosa?

Abstract

The exact medical complications, leading to the well-known high risk of death in patients with anorexia nervosa (AN), remain elusive. Such deaths are often abrupt with no satisfactory explanation. Suspected causes include cardiac QTc prolongation and, in turn, torsade de pointes (TdP). Psychotropic medications often prescribed to these patients are linked to QTc prolongation. AN is also presumed to cause heart failure due to malnutrition with increased susceptibility to QTc prolongation, and TdP, resulting in sudden cardiac death. Recent literature, however, is conflicting, and the likely cause of death may involve other cardiac abnormalities, such as low heart rate, abnormal heart rate variability, or increased QT dispersion. With an ongoing gap in research explaining the high mortality rate in AN, a compelling need to define the exact proximate causes of death in these patients remains. Because low serum potassium is the most common trigger for TdP, we postulate the early signal of sudden cardiac death, especially in patients with AN who purge, is hypokalemia. We also speculate that hypoglycemia could be a major factor in the sudden death of patients with AN as well as bradycardia or sinus arrest. A path forward to elucidate potential causes is offered.