The QTc interval and risk of cardiac events in bulimia nervosa: A long‐term follow‐up study

Abstract

Objective An association between bulimia nervosa (BN) and prolonged corrected QT interval (QTc) in the electrocardiogram has been suggested, but results of previous studies are conflicting, and the risk of cardiac events in patients with BN has yet to be investigated. Method We estimated mean QTc interval and relative risk of borderline (QTc >440 ms) and prolonged QTc (QTc >460 ms) between adult women with BN (N = 531) and healthy controls (N = 123). In follow‐up analyses, we investigated the risk of a primary endpoint (syncope, ventricular tachycardia, and cardiac arrest) and all‐cause mortality in patients with BN (N = 702) compared with a population‐based cohort derived from the Danish Civil Register (N = 7,020). Results Mean QTc did not differ between patients with BN and controls. Relative risk of borderline prolonged QTc was 2.3 (p = 0.28). The number of patients and controls with prolonged QTc was small, and the risk did not differ between patients with BN and controls. Median follow‐up was 10.6 years. Although there appeared to be increased risks after 5 years of follow‐up, long‐term risks of the primary endpoint (Hazard ratio [HR] = 1.4, p = 0.37) and all‐cause mortality (HR = 1.7, p = .28), respectively, were not increased in patients with BN compared to a population‐based cohort. Discussion Mean QTc did not differ between patients with BN and healthy controls, and the risk of prolonged QTc was not increased in patients with BN. There was no difference in the long‐term risk of cardiac events, and long‐term all‐cause mortality did not differ significantly between patients with BN and a population‐based cohort.

Association of Bulimia Nervosa With Long-term Risk of Cardiovascular Disease and Mortality Among Women

“…1 Electrical conduction defects in bulimia coincide with electrolyte imbalance and hypokalemia. [19][20][21] In women diagnosed with severe bulimia and hypokalemia, QT interval prolongation and repolarization abnormalities may lead to sudden acute ventricular arrhythmias and death. 21 A study of 52 women diagnosed with bulimia in the United States who binged and purged found a lower R-wave amplitude on the electrocardiogram, indicating reduced cardiac contractile force and signaling.…”

“…Most of the literature focuses on acute consequences, including immediate hemodynamic changes and electrical conduction defects due to excessive purging and fluid loss. [19][20][21] Bulimia is associated with reduced blood pressure, pulse rate, and oxygen saturation during active disease. 1 Electrical conduction defects in bulimia coincide with electrolyte imbalance and hypokalemia.…”

“…A recent study in Denmark of 531 women with bulimia and 125 women without found no evidence of an association of bulimia with QT prolongation or with immediate cardiac events and all-cause mortality. 20 Regardless of the short-term association between bulimia and cardiac events, it is likely that conduction defects due to electrolyte imbalance are reversible. 21 Bulimia nervosa is associated with metabolic changes that have the potential to affect the risk of chronic nonreversible cardiovascular disease.…”

“…Little is known about the mid- to long-term associations of bulimia nervosa with the cardiovascular system. Most of the literature focuses on acute consequences, including immediate hemodynamic changes and electrical conduction defects due to excessive purging and fluid loss . Bulimia is associated with reduced blood pressure, pulse rate, and oxygen saturation during active disease .…”

Early repolarization pattern in adult females with eating disorders

“…Recently, a large register‐based study found that the risk of ventricular tachycardia and syncope is increased in patients with AN compared with the background population (Frederiksen, Krogh Christiansen, et al., 2018), which is in line with the previous theory that an increased risk of QTc prolongation on the ECG, and subsequently polymorphic ventricular tachycardia, could partly explain the increased cardiovascular death in patients with AN (Sachs et al., 2016). However, the three largest studies on the matter found no increased risk of QTc prolongation in patients with AN or BN (Frederiksen, Christiansen, et al., 2018; Frederiksen, Krogh Christiansen, et al., 2018; Krantz et al., 2020). Therefore, the background for the increased risk of cardiovascular death in these patients is still unresolved.…”