Resting heart rate as a prognostic factor for mortality in patients with breast cancer.

Although elevated resting heart rate (RHR) has been shown to be associated with mortality in the general population and patients with certain diseases, no study has examined this association in patients with breast cancer. A total of 4786 patients with stage I-III breast cancer were retrospectively selected from the Severance hospital breast cancer registry in Seoul, Korea. RHR was measured at baseline and the mean follow-up time for all patients was 5.0 ± 2.5 years. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were calculated using Cox regression models. After adjustment for prognostic factors, patients in the highest quintile of RHR (≥85 beat per minute (bpm)) had a significantly higher risk of all-cause mortality (HR: 1.57; 95 %CI 1.05-2.35), breast cancer-specific mortality (HR: 1.69; 95 %CI 1.07-2.68), and cancer recurrence (HR: 1.49; 95 %CI 0.99-2.25), compared to those in the lowest quintile (≤67 bpm). Moreover, every 10 bpm increase in RHR was associated with 15, 22, and 6 % increased risk of all-cause mortality, breast cancer-specific mortality, and cancer recurrence, respectively. However, the association between RHR and cancer recurrence was not statistically significant (p = 0.26). Elevated RHR was associated with an increased risk of mortality in patients with breast cancer. The findings from this study suggest that RHR may be used as a prognostic factor for patients with breast cancer in clinical settings.