Autonomic Nerve Function Predicts Risk of Early Death after Discharge in Acute Medical Disease

• Published in: The American journal of medicine Vol. 137; no. 7; pp. 649 - 657.e2
• Main Authors: Hadad, Rakin, Haugaard, Steen B., Christensen, Philip Bonde, Sarac, Ayse, Dominguez, Maria Helena, Sajadieh, Ahmad
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2024
• Subjects: Acute Disease; Acute medicine; Aged; Aged, 80 and over; Autonomic Nervous System - physiopathology; Cardiac autonomic function; Cardiology; Female; Heart Rate - physiology; Heart rate variability; Humans; Internal medicine; Male; Middle Aged; Patient Discharge - statistics & numerical data; Patient Readmission - statistics & numerical data; Prognosis; Prospective Studies; Cardiac autonomic function; Acute medicine; Internal medicine; Cardiology; Heart rate variability
• ISSN: 0002-9343; 1555-7162; 1555-7162
• DOI: 10.1016/j.amjmed.2024.02.033

Heart rate variability, a marker of autonomic function, has shown promising prognostic results in specific populations, but has not been tested in a general medical population. We hypothesized that heart rate variability identifies high-risk medical patients early after admission to the hospital. This was a single-center prospective cohort study of acutely admitted medical patients aged ≥18 years with a life expectancy ≥3 months, included between 2019-2023. Unstable patients needing direct admission to the intensive care unit were excluded. Heart rate variability was recorded within 24 hours of admission for 10 minutes. The standard deviation of normal-normal beats (SDNN) was the primary heart rate variability marker. Low SDNN was defined as the lowest tertile (≤22 ms). The primary outcome was 30-day all-cause mortality. The secondary outcome was 30-day readmission or mortality. Among 721 patients included, low SDNN carried an 8-fold greater risk of 30-day mortality in univariate analysis (hazard ratio [HR] 8.3; P = .001); in multivariate analyses a 4-fold greater risk (HR 3.8; P = .037). Low SDNN was associated with the combined outcome of 30-day mortality or readmission (HR 1.5; P = .03) in multivariate analysis. In receiver operating characteristics analyses, low SDNN improved the predictive accuracy of early warning score for 30-day mortality or readmission from 0.63 to 0.71 (P = .008) but did not improve the accuracy for 30-day mortality alone. In patients admitted due to acute medical illness, low heart rate variability predicted 30-day mortality and readmission, suggesting heart rate variability as a tool to identify patients at high and low risk of relevant endpoints. [Display omitted]