Endocrine Abstracts

Background: Metabolic syndrome (MetS) represents a huge public health problem worldwide, being associated with an increased risk of cardiovascular and oncological diseases, and all-cause mortality. There is compelling evidence supporting a key role of dysfunctional autonomic nervous system (ANS) in such an association as well as the mutual correlation between the components of MetS. Autonomic Nervous System Index (ANSI) is a percent ranked (0–100) unitary proxy of cardiac autonomic regulation (CAR), extracted from the autoregressive spectral analysis of heart rate variability (HRV) by combining the three most informative indexes. It is a simple and non-invasive method to evaluate and monitor ANS function, being by design free of age and gender bias ¹.

Aims: To investigate CAR by means of ANSI in patients affected with MetS.

Methods: 133 patients referred to the Exercise Medicine Clinic of Istituto Auxologico IRCCS underwent assessment of CAR - by means of ANSI - alongside lifestyle with ad hoc questionnaires focusing on weekly physical activity volume, nutrition quality, and perception of stress, fatigue and somatic symptoms. Participants were retrospectively subdivided into two groups according to the presence or not of MetS criteria (established by the Joint Interim Statement in 2009 ²).

Results: 58 subjects were affected with MetS, while 75 were not (non-MetS). Non-MetS patients were characterized by a significant prevalence of females and lower age as compared with MetS counterpart. ANSI (free of age and gender bias) was significantly impaired (32.9 vs 44.8, P=0.007) in MetS subset. No significant differences were found in terms of lifestyle between the groups.

Conclusions: This is the first study assessing CAR by means of ANSI in MetS patients. Such findings indicate neurovegetative dysregulation in MetS. Intriguingly, in view of the increased cardiovascular risk mediated via - among others – ANS impairment in MetS, early screening for ANS dysfunction with simple but reliable methods may be clinically advantageous, with a view to undertaking and monitoring therapeutic strategies that aim to restore autonomic balance (e.g., personalized lifestyle management programs).

Reference: Sala R, et al. A Composite Autonomic Index as Unitary Metric for Heart Rate Variability: A Proof of Concept. Eur. J. Clin. Invest. 2017, 47, 241–249.

Alberti, K.G.M.M., et al. Harmonizing the Metabolic Syndrome: A Joint Interim Statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International. Circulation 2009, 120, 1640–1645.