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

Electrocardiographic QTc as a Surrogate Measure of Cardiac Risk in Children, Adolescents, and Young Adults With Eating Disorders

The study goal was to investigate electrocardiographic findings, including corrected QT interval (QTc), in patients aged 8 to 23 with eating disorders (EDs) at presentation, compared with an age-and sex-matched control population. We retrospectively reviewed 200 ED patients, and 200 controls. Blinded electrocardiograms (ECGs) were interpreted by an expert reader, and QT intervals corrected using the Bazett formula. Eating disorder patients were 89.5% female, with mean age 16.4 years and median percent median body mass index (BMI)-for-age (%mBMI)a of 91.1%. In ED patients, QTc was significantly shorter than controls (399.6 vs 415.0msec, P < .001). After adjusting for height, %mBMI, sex, magnesium level, and bradycardia, mean QTc duration in patients with anorexia nervosa-restricting subtype (AN-R) was significantly shorter than other ED patients (P = .010). Higher %mBMI was associated with shorter QTc duration (P = .041) after adjusting for height, magnesium, bradycardia, and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis. Within the ED group, no significant association was identified between QTc and medications, electrolytes, or inpatient status.

Early repolarization pattern in adult females with eating disorders

INTRODUCTION

The risk of cardiovascular death is increased in patients with eating disorders (ED), but the background for this is unknown. Early repolarization pattern (ERP) on the electrocardiogram (ECG) has been associated with increased risk of sudden cardiac death.

METHODS

We investigated the prevalence of ERP in 233 female patients with anorexia nervosa (AN) and bulimia nervosa (BN) (age 18-35 years) compared with 123 healthy female controls.

RESULTS

Early repolarization pattern was present in 52 (22%) of ED patients (16 (15%) AN patients and 36 (29%) BN patients) and 17 (14%) of healthy controls. When adjusting for age, BMI, heart rate, use of selective serotonin reuptake inhibitors (SSRI), and potassium level, the odds ratio (OR) for ERP was 2.1 (95% CI 1.1-4.2, p = .03). There was an increased prevalence of inferolateral ERP in patients with ED compared with healthy controls (OR = 4.3, 95% CI 1.7-11.3, p = .003) as well as ERP with a downward/horizontal sloping ST segment (OR = 3.1, 95% CI 1.3-7.6, p = .01). Additionally, J-point elevation >0.2 mV was more prevalent in patients with ED (OR = 3.3, 95% CI 1.1-9.7, p = .03).

CONCLUSION

The prevalence of ERP was increased in patients with ED compared with healthy controls. This finding may provide a possible explanation for the increased cardiovascular mortality in ED patients.

T-wave morphology descriptors in patients with bulimia nervosa

PURPOSE

Bulimia nervosa (BN) is associated with increased risk of cardiovascular disease and arrhythmias. Some reports found abnormal electrocardiographic markers of arrhythmias in BN, while others did not. This study investigated novel parameters of T-wave morphology that were reported to be associated with adverse cardiovascular outcomes in other patient groups, among patients with BN under medical care.

METHOD

Thirty-five BN patients and 76 healthy controls were included. Total cosine R to T (TCRT) and T-wave Morphology Dispersion (TMD) parameters were computed according to accepted standards for an average beat and a random beat. Patients were followed for 11.1 ± 0.1 years for the emergence of arrhythmias or events of sudden death.

RESULTS

Twenty-five (71.4%) BN patients were hospitalized when enrolled, for a mean duration of 1.1 ± 0.2 months. The rest were ambulatory patients. The BN group had lower blood pressure, more smokers, and used antidepressants, neuroleptic drugs and benzodiazepines more than controls did. Other demographic parameters were comparable between groups. TCRT and TMD parameters were statistically similar and within the normal ranges reported by other research groups. None of the BN patients had prolonged QTc interval or electrolyte abnormalities on inclusion. During the follow-up period, no clinical symptoms suggestive of arrhythmias were reported, and no cardiovascular-related hospitalizations or deaths occurred in either group.

CONCLUSION

Medically treated BN patients have normal T-wave morphology parameters and hence, low risk for repolarization-associated malignant ventricular arrhythmias. The prognostic importance of these novel repolarization parameters remains to be explored among untreated patients, those who ingest emetic substances and patients with electrolyte imbalance.

LEVEL OF EVIDENCE

Level III.

Is QTc-Interval Prolongation an Inherent Feature of Eating Disorders? A Cohort Study

BACKGROUND

Anorexia nervosa is associated with a markedly increased risk of sudden cardiac death, but the mechanism has not been elucidated. Whether QT prolongation is an intrinsic feature of eating disorders is uncertain because previous studies are limited by small sample size, and extrinsic factors associated with QT prolongation were inconsistently reported. This study set to determine population-mean heart-rate-corrected QT interval (QTc) in an unselected cohort of patients with eating disorders.

METHODS

Electrocardiogram (ECG) data from 1026 consecutive adults admitted into residential treatment were stratified by subtype: anorexia nervosa (caloric restriction only), anorexia nervosa binge-purge, and bulimia nervosa. Eating disorders not otherwise specified were excluded. Population-mean Fridericia-corrected QTc and categorical QTc threshold analysis were performed. Multivariable regression, controlling for age sex, duration of illness, body mass index (BMI), hypokalemia, QTc-prolonging drugs, purging behaviors, and laxatives was assessed.

RESULTS

Among 906 patients, population-mean QTc (424 ± 25 standard deviation [SD]) was normal and lowest among patients with anorexia nervosa (417.3 ± 22.3, P <0.001 vs other subgroups). Only 1.2% (N = 11) had marked QTc prolongation (QTc >500 ms); all 11 patients had hypokalemia and were receiving QTc-prolonging medications or laxatives. After controlling for clinically relevant covariates, differences in mean QTc across eating disorder subtypes diminished yet persisted (P = 0.048).

CONCLUSIONS

In the largest study of patients with eating disorders, population-mean QTc was normal and varied by subtype. Marked QTc prolongation occurred solely in the presence of extrinsic factors, suggesting that QTc prolongation is not intrinsic to eating disorders. Therefore, further study is needed to define the etiology of sudden death in patients with eating disorders.

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

IMPORTANCE

Bulimia nervosa is associated with short-term cardiovascular complications in women, but its long-term consequences on cardiovascular health are unknown.

OBJECTIVE

To study the association of bulimia nervosa with the long-term risk of cardiovascular disease and mortality in women.

DESIGN, SETTING, AND PARTICIPANTS

In this longitudinal cohort study, 416 709 women hospitalized in Quebec, Canada, including women hospitalized for bulimia nervosa and those for pregnancy-related events as a comparison group, were followed up for 12 years from 2006 to 2018 to identify incidences of cardiovascular disease and death.

EXPOSURES

At least 1 hospitalization for bulimia nervosa.

MAIN OUTCOMES AND MEASURES

The study participants were followed up to identify future incidences of cardiovascular disease and deaths. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs to assess the association of bulimia nervosa with future outcomes after adjustment for patient characteristics.

RESULTS

The study population comprised 818 women who were hospitalized for bulimia nervosa (mean [SD] age, 28.3 [13.4] years) and 415 891 hospitalized for pregnancy-related events (mean [SD] age, 28.3 [5.4] years). Patients were followed up for a total of 2 957 677 person-years. The women hospitalized for bulimia nervosa had a greater incidence of cardiovascular disease compared with those hospitalized for pregnancy-related events (10.34 [95% CI, 7.77-13.76] vs 1.02 [95% CI, 0.99-1.06] per 1000 person-years). Incidence of future cardiovascular disease was even higher for women with 3 or more bulimia admissions (25.13 [95% CI, 13.52-46.70] per 1000 person-years). Women hospitalized for bulimia nervosa had 4.25 (95% CI, 2.98-6.07) times the risk of any cardiovascular disease and 4.72 (95% CI, 2.05-10.84) times the risk of death compared with women hospitalized for pregnancy-related events. Bulimia nervosa was found to be associated with ischemic heart disease (HR, 6.63; 95% CI, 3.34-13.13), atherosclerosis (HR, 6.94; 95% CI, 3.08-15.66), and cardiac conduction defects (HR, 2.99; 95% CI, 1.57-5.71). Bulimia was also associated with 21.93 (95% CI, 9.29-51.74) times the risk of myocardial infarction at 2 years of follow-up and 14.13 (95% CI, 6.02-33.18) times the risk at 5 years of follow-up.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that bulimia nervosa may be associated with the long-term risk of any cardiovascular disease, such as ischemic cardiac events and conduction disorders, as well as with death among women. The findings also suggest that women with a history of bulimia nervosa should be screened regularly for ischemic cardiovascular disease and may benefit from prevention of and treatment for cardiovascular risk factors.