Hypertension is a major chronic disease managed by primary healthcare institutions in China. Cardiac autonomic dysfunction is a key cause of blood pressure regulation imbalance and adverse cardiovascular events. Therefore, in primary healthcare institutions, the use of efficient and portable single lead wearable electrocardiogram (ECG) devices can help explore the relationship between elderly hypertensive patients and the autonomic nervous system, providing a simple, efficient, low-cost, and sustainable suitable method and objective basis for the management and prevention of cardiovascular disease in primary hypertensive patients.

To investigate the correlation between the duration of hypertension and autonomic nervous system damage in elderly patients in Primary Care institutions in the Ningxia Hui Autonomous Region using a single lead wearable ECG device.

A total of 2 137 elderly hypertension patients aged 65 years or older from 20 primary medical institutions in the Ningxia Hui Autonomous Region were enrolled in this study. ECG data of 72 hours, along with basic information, psychological health, and lifestyle data, were collected and uploaded to the cloud platform using a single-lead wearable ECG device from January 2022 to December 2022. Based on the heart rate variability (HRV) time-domain parameter standard deviation of all sinus rhythm RR intervals (SDNN), subjects were divided into two groups: a normal group (SDNN>100ms, n=470) and an abnormal group (SDNN<100 ms, n=1 667). Propensity score was used to match subjects on a 1∶1 basis, adjusting for confounding factors with a caliper value of 0.02, and the matching effect was verified using inverse probability weighting. Single-factor and multivariate Logistic regression analyses were conducted to investigate the relationship between the onset of hypertension and autonomic nerve damage, and the matching effect was further verified. Subgroup analyses were performed using propensity score matching based on the onset of hypertension and autonomic nerve damage, with sensitivity analyses conducted before and after matching. Additionally, a nonlinear association between the duration of hypertension and autonomic nerve damage was examined using restricted cubic splines (RCS) analysis to test interaction effects.

Among the patients, 479 had grade 1 hypertension, and 1 658 had grade 2 hypertension. Disease duration was categorized as follows: 1 203 patients had less than 5 years of disease duration, 753 had 5-<10 years, 110 had 10-<15 years, 41 had 15-<20 years, 26 had 20-<30 years, and 4 had more than 30 years. The multivariate Logistic regression analysis showed that the relationship between autonomic nerve damage and hypertension duration was positive after matching (P<0.001). Subgroup analysis showed that the relationship between hypertension duration and autonomic nerve damage was stronger in the 80-year-old and younger, lower-educated, no comorbidities of coronary heart disease, female, and those with obstructive sleep apnea (OSA) subgroups before and after matching, with statistically significant differences (P<0.05) and interaction effects (P<0.05). However, the RCS analysis showed no nonlinear relationship between the course of hypertension and autonomic nerve damage in matched patients.

There was a positive correlation between the course of hypertension and autonomic nerve damage in elderly hypertension patients from the primary healthcare centers of the Ningxia Hui Autonomous Region. Primary healthcare facilities should strengthen health education for patients to improve their treatment adherence, which can delay autonomic nerve damage in hypertensive patients.