# Association of sleep disturbance during breast cancer treatment and left ventricular ejection fraction decline: a prospective cohort study

## TL;DR

This study shows that sleep problems during breast cancer treatment may be linked to heart function decline, suggesting sleep could be a key factor in heart health for cancer patients.

## Contribution

The study identifies sleep disturbance as a potential modifiable risk factor for left ventricular ejection fraction decline in breast cancer patients.

## Key findings

- A 10-point increase in sleep disturbance was associated with a 1.31%-point reduction in left ventricular ejection fraction.
- Sleep disturbance was linked to early signs of subclinical cardiac dysfunction independent of general health decline.
- The association remained significant after adjusting for baseline risk factors and health changes.

## Abstract

Sleep disturbances during breast cancer (BC) treatment may represent a modifiable contributor to left ventricular ejection fraction (LVEF) decline during BC treatment. We investigated the association of sleep disturbance and LVEF decline in a prospective cohort of 247 women with non-metastatic BC scheduled for chemotherapy as part of the UPBEAT study conducted through the Wake Forest NCI Community Oncology Research Program Research Base (WF NCORP RB; WF-97415, UG1CA189824). Participants completed cardiac magnetic resonance imaging to measure LVEF, six-minute walk distance, and validated surveys assessing sleep disturbance, physical health, and mental health at baseline and 3 months. Sleep disturbance was measured using the Patient Reported Outcomes Measurement Information System Sleep Disturbance survey. At 3-month follow-up, 30.3% of participants experienced a clinically meaningful increase in sleep disturbance, with a mean LVEF decline of -4.13%-points compared to -1.93%-points in those without increased disturbance (p = 0.10). In multivariable models adjusting for baseline risk factors and concurrent changes in health, a 10-point increase in sleep disturbance was associated with a 1.31%-point reduction in LVEF (β= -0.131; 95% CI: -0.24,-0.02; p = 0.02). Associations were robust across sensitivity analyses. This study provides evidence linking sleep disturbance during BC treatment to early LVEF decline, suggesting sleep disturbance may contribute to subclinical cardiac dysfunction independent of general health decline. Longitudinal studies incorporating objective sleep measures are warranted to clarify mechanisms and evaluate whether behavioral interventions targeting sleep could mitigate cardiovascular risk in BC survivors.