Objective: Currently, the diagnosis of dysautonomia relies on specialized tests available only in a minority of tertiary centers. The objective of this study was to assess the ability of blood pressure (BP) and heart rate (HR) variability derived from 24-hour ambulatory blood pressure monitoring (ABPM) to differentiate patients with neurogenic dysautonomia from propensity-matched controls. Design and method: This matched case-control study included 51 patients with established neurogenic dysautonomia, mostly diagnosed in the context of Parkinson disease, and 51 controls matched for age, sex, body mass index and renal function. BP variability was assessed by standard deviation (SD), weighted standard deviation (wSD), average real variability (ARV) and coefficient of variation (CV). HR variability was assessed by SD and CV. Results: The mean age of participants was 76 years, and 31.4% were women. Mean 24-hour systolic BP did not differ between patients with dysautonomia and controls (137.5 ± 17.8 vs 132.4 ± 12.7 mmHg; p = 0.105). However, nocturnal systolic BP dipping was markedly attenuated or reversed in patients with dysautonomia (-1.6 ± 13.0% vs 8.2 ± 8.3%; p < 0.001), and 24-hour systolic BP variability was significantly increased (wSD 21.6 ± 6.3 vs 15.6 ± 4.3 mmHg; p < 0.0001; CV 16.7 ± 4.1 vs 12.9 ± 3.2%; p < 0.0001). In contrast, neither mean HR nor HR variability differed significantly between groups (HR CV 11.8 ± 4.0 vs 13.1 ± 4.5%; p = 0.14). A multivariable logistic regression model incorporating 24-hour systolic BP CV and reverse dipping status showed good discriminative performance (AUC = 0.801; 95% CI 0.71–0.89; p < 0.001). At a Youden index of 0.484, both sensitivity and specificity were 70.6%. Conclusions: Neurogenic dysautonomia is associated with a distinctive ABPM profile characterized by increased BP variability and impaired nocturnal dipping, without compensatory changes in HR variability. Compared to matched controls, BP variability was consistently increased using indices independent of mean BP and dipping status. These preliminary results pave the way for development of simple, widely applicable ABPM-based criteria for the diagnosis of neurogenic dysautonomia.
Piotte et al. (Fri,) studied this question.