Impaired autonomic function is associated with increased mortality, especially in subjects with diabetes, hypertension, or a history of cardiovascular disease - The Hoorn study

OBJECTIVE - Measures of baroreflex sensitivity, heart rate variability (HRV ), and the classical Ewing test parameters are currently used for the diagn osis of diabetic autonomic neuropathy and for mortality risk stratification after myocardial infarction. However, the strengths of the associations of these measures of autonomic function with risk of mortality have never bee n e possible e compare in one study population. Furthermore, no evidence is available on tof glucose tolerance on these associations. RESEARCH DESIGN AND METHODS - The study population (n = 605) consisted of a glucose tolerance-stratified sample from a general population (50-75 years of age). Cardiac cycle duration and continuous finger arterial pressure we re measured under two conditions: at rest and on metronome breathing. From these readings, seven parameters of autonomic function were assessed (one E wing, five HRV, and one baroreflex sensitivity), RESULTS - During 9 years of follow-up, 101 individuals died, 43 from cardio vascular causes. Subjects with diabetes and low levels of the autonomic fun ction parameters, indicating impaired autonomic function, had an approximat ely doubled risk of mortality. This association. was consistent, though not statistically significant, for all parameters. The elevated risk was not o bserved in subjects without diabetes, hypertension, or prevalent cardiovasc ular disease. CONCLUSIONS - impaired autonomic function is associated with all-cause and cardiovascular mortality. Moreover, the results of the present study sugges t that cardiac autonomic dysfunction in patients already at risk (diabetes, hypertension, or history of cardiovascular disease) may be especially haza rdous.