In patients with type 1 diabetes and increased ankle-brachial index (ABI), a marker of arterial stiffness, there is a 3-fold increase in the risk for cardiovascular autonomic neuropathy, according to study results published in The Journal of Clinical Endocrinology & Metabolism. The highest risk was found in patients with both increased ABI and asymptomatic peripheral arterial disease (PAD).
Cardiovascular autonomic neuropathy is a frequent complication of type 1 diabetes that often remains undiagnosed and may lead to significant morbidity and mortality. Reduced heart rate variability is an important early finding in patients with cardiovascular autonomic neuropathy that can lead to earlier diagnosis.
Investigators studied the risk for cardiovascular autonomic neuropathy in patients with type 1 diabetes and arterial stiffness, defined by an ABI >1.2. Diagnosis of cardiovascular autonomic neuropathy was determined based on changes in blood pressure and heart rate according to a modified Ewing Score.
The cross-sectional study included 264 adults with type 1 diabetes (mean age, 35 ± 11 years; mean glycated hemoglobin, 7.5% ± 1.3%) from an academic hospital. The investigators reviewed the medical records of the patients and assessed ABI, which was categorized as normal (ABI, 0.91-1.20), reduced (ABI ≤0.9), or increased (ABI >1.2). In all patients with increased ABI, a combination of toe-brachial index and peripheral artery Doppler ultrasound was used to evaluate for asymptomatic PAD.
Increased ABI was found in 73 patients (28%) and these patients were older and had higher body mass index, waist circumference, and blood pressure measurements. In 28 of these patients, there was also evidence of asymptomatic PAD.
Diagnosis of cardiovascular autonomic neuropathy was significantly more common in patients with arterial stiffness compared with patients with normal ABI (48% vs 23%; odds ratio [OR], 3.1; 95% CI, 1.7-5.4; P <.001). In patients with arterial stiffness and asymptomatic PAD, the risk for cardiovascular autonomic neuropathy was even greater (OR, 4.5; 95% CI, 2.0-10.1) compared with patients with normal ABI.
The importance of arterial stiffness persisted even following adjustment for asymptomatic PAD and the presence of other cardiovascular risk factors.
The investigators acknowledged potential limitations to their study, including a cohort composed almost entirely of white Hispanic patients who were treated in a highly specialized diabetes center and did not have severe microvascular or macrovascular complications.
Routine use of a noninvasive method like ABI “may identify a subset of patients with undiagnosed [cardiovascular autonomic neuropathy] who may benefit from an early and aggressive management of cardiovascular risk factors,” concluded the researchers.
Nattero-Chavez L, López SR, Díaz SA, et al. Association of cardiovascular autonomic dysfunction with peripheral arterial stiffness in patients with type 1 diabetes [published online February 20, 2019]. J Clin Endocrinol Metab. doi:10.1210/jc.2018-02729