Abstract
AIM: We aim to determine the impact of multiday heart rate variability (HRV) on the risk of major adverse cardiovascular events (MACE), heart failure and mortality in people at high risk of diabetes. MATERIALS AND METHODS: Multiday HRV and mean heart rate (mHR) were measured in 1627 participants from the ADDITION-PRO study between 2009 and 2011. As measurement for HRV, we calculated a proxy for standard deviation of normal heartbeat (SDNN) both weekly, daily and hourly. Data on MACE and all-cause mortality were obtained from Danish patient registers until 2021. We fitted Poisson regression to determine incidence rate ratios (IRR) for MACE (myocardial infarction, stroke and cardiovascular death), heart failure and all-cause mortality. RESULTS: Mean (SD) age was 66 years (7), and 47% were women. The population had a mean (SD) multiday SDNN of 139.0 (32.3) milliseconds. Multiday HRV index SDNN showed an IRR of 0.82 (CI: 0.69; 0.97), 0.76 (CI: 0.58; 0.99) and 0.79 (CI: 0.66; 0.94) per SD for MACE, heart failure and all-cause mortality, respectively. SDNN measurements taken from 6:00 AM to 7:00 AM showed the strongest association with the risk of MACE. Lower SDNN was associated with all-cause mortality across all hours of the day. Adjustment for physical acceleration and heart rate did not materially change the magnitude of these associations. CONCLUSION: Cardiovascular autonomic dysfunction, measured by multiday HRV, is linked with MACE, heart failure and all-cause mortality. Certain time frames of the day for HRV and heart rate under free-living conditions showed a higher risk of cardiovascular disease.