Effect of mean heart rate on 30-day mortality in older patients with sepsis: Data from the MIMIC-IV database

Background: Sepsis is a critical condition with a significant risk of mortality. Advanced age is one factor in increasing mortality in intensive care. Objectives: The aim of this study is to investigate the association between mean heart rate (MHR) and 30-day mortality among older patients with sepsis in the intensive care unit (ICU). Methods: All older patients (age 65 or older) with sepsis for first time in ICU admission in Medical Information Mart for Intensive Care-IV (MIMIC-IV) were included in this retrospective study. The effect of MHR within 24 h of ICU admission on 30-day mortality was assessed according to multivariable Cox regression models, restricted cubic splines and two-piecewise Cox regression models. Results: The total number of participants was 6598 (mean heart rate, 83.8 14.3 bpm). A total of 1295 (19.6%) patients died within 30 days after ICU admission. MHR within 24 h of admission was associated with 30-day mortality (J-shaped association) in older patients with sepsis in the ICU, with an inflection point at about 74 bpm and a minimal risk observed at 73 to 82 bpm of MHR. Conclusions: In this retrospective cohort study, there was a J-shaped association between MHR and 30-day mortality in older patients with sepsis admitted to the ICU and a minimal risk observed at 73 to 82 bpm of MHR. If further confirmed, this association may provide a theoretical basis for formulating the target strategy of heart rate therapy for these patients.