A30-13 Nocturnal Heart Rate Variability and Heart Rate Response to Respiratory Events in Type 2 Diabetes Patients

Abstract Introduction Type 2 diabetes (T2D) is associated with increased morbidity and mortality, partly through cardiac autonomic neuropathy. Heart rate variability (HRV) is an established marker to quantify autonomic dysfunction. Heart rate response to apneas and hypopneas (ΔHR) is a specific aspect of HRV that has been associated with increased risk for cardiovascular disease. We investigated whether HRV and ΔHR from polygraphy predict major adverse cardiovascular events (MACE) and mortality in T2D. Methods HRV and ΔHR were assessed in the DIACORE (DIAbetes COhoRtE) sleep-disordered breathing sub-study, a prospective cohort study of T2D patients. MACE was defined as myocardial infarction, stroke, and cardiovascular death. We performed Cox hazard regression analyses adjusted for potential known risk factors for atherosclerosis - e.g. age, sex, waist-hip-ratio, smoking status, hypertension, and diabetes duration - as well as betablocker use to test the association between ΔHR and HRV and the incidence of MACE and all-cause mortality. Results Among 1009 participants (40% female, mean age 67 years, mean diabetes duration 9.7 years) a MACE occurred in 121 (12%) patients, and 97 (10%) died after a median follow-up of 6.5 years. Patients with high ΔHR (upper quartile) had a 56% increased risk for MACE compared to patients with midrange ΔHR (25th to 75th percentiles) (adjusted hazard ratio 1.56, 95% confidence interval (CI) 1.03-2.36, p = 0.035). HRV was not associated with incident MACE. Mortality was significantly increased in patients with either low standard deviation of normal to normal intervals (adjusted hazard ratio 1.72, 95% CI 1.06; 2.78, p = 0.028) or low root mean square of successive differences between heartbeats (adjusted hazard ratio 2.34, 95% CI 1.44; 3.80, p 0.001) compared to patients in the mid-range (Q2-Q3). In contrast, ΔHR quartiles were not significantly associated with mortality. Conclusion T2D patients with high ΔHR are at increased risk for incident MACE while low nocturnal HRV is associated with higher overall mortality. Both may have a complementary role in risk stratification for cardiovascular events and mortality in T2D patients with sleep disordered breathing. This abstract is funded by: KfH Stiftung Präventivmedizin e.V., the Else Kroener-Fresenius Stiftung, and the Dr. Robert Pfleger-Stiftung. The DIACORESDB sub-study has been funded by ResMed (Martinsried, Germany), and ResMed Foundation.