Heart rate variability in patients with Parkinson's disease complicated with orthostatic hypotension

Orthostatic hypotension (OH) is a major presentation of autonomic dysfunction in Parkinson's disease (PD). Heart rate variability (HRV) can be used to detect abnormal changes in autonomic function at an early stage. The current study aimed to identify PD patients with OH at an early stage, analyzing HRV indexes. A total of 170 PD patients were continuously recruited and divided into PD with OH (PD-OH, n = 55) or PD with no OH (PD-NOH, n = 115) groups, based on blood pressure values measured in both supine and upright positions. General demographic and clinical data were recorded. The PD-OH group showed significantly older age, longer disease duration, more diabetes cases, more coronary heart disease cases, higher levels of fasting blood glucose, higher levels of glycated hemoglobin A1c, higher levodopa-equivalent daily doses, higher Hoehn-Yahr stage, higher Unified PD Rating Scale III scores, and higher Scale for Outcomes in PD for Autonomic Symptoms than the PD-NOH group (P < 0.05). HRV indices were acquired by analyzing 24-hour ambulatory electrocardiograms. Compared with the PD-NOH group, HRV indices, including the standard deviation of all normal-normal intervals (SDNN), SDNN index, standard deviation of the average normal-normal intervals (SDANN), and HRV triangular index, were clearly lower in the PD-OH group (P < 0.05). Using variables, p values < 0.10 between the PD-OH and PD-NOH groups as independent variables, as well as the presence or absence of OH as dependent variables, multivariate logistic regression was performed. Results showed that age (B, 0.085; OR value, 1.088; 95% CI, 1.033 similar to 1.146; P < 0.05) and SDNN (B, -0.047; OR value, 0.954; 95% CI, 0.912 similar to 0.998; P < 0.05) were independent related factors for patients in the PD-OH group. In summary, age was an independent risk factor for development of OH in PD patients. Reduced SDNN was independently related to PD with OH.