Association of heart rate variability index with depressive symptoms and lung function in chronic obstructive pulmonary disease

Abstract

BACKGROUND

Depression is a common comorbidity in patients with chronic obstructive pulmonary disease (COPD). Research indicates that COPD affects cardiac autonomic control, and heart rate variability (HRV) serves as a simple, non-invasive measure of autonomic nerve activity. However, the relationship between HRV and lung function, as well as the impact of depressive symptoms, remains unclear.

AIM

To investigate the correlation between HRV indicators and depressive symptoms and lung function in patients with COPD.

METHODS

A retrospective cross-sectional study involving 120 COPD patients hospitalized from January 2018 to January 2024 at our institution was conducted. Demographic and clinical characteristics were collected, and depressive symptoms were assessed using the Beck Depression Inventory (BDI). Patients were categorized into a depressed group (BDI ≥ 16) and a non-depressed group (BDI < 16). A control group consisting of 60 healthy volunteers who underwent check-ups at the same institution was also included. Statistical analyses were performed using SPSS 26.0 software. Pearson correlation coefficients were calculated to determine and compare the relationships between HRV parameters, lung function measures, and depressive symptoms across the groups.

RESULTS

Of the 120 patients with COPD, 35.8% (43/120) were diagnosed with depression, compared to 5.0% (3/60) in the control group. The HRV index in COPD patients was significantly lower than that in the control group (P < 0.05), and the value in the depressed group was significantly lower than that in the non-depressed group (P < 0.05). Similarly, the COPD group had a significantly lower pulmonary forced vital capacity (FVC), first-second expiratory volume (FEV1) and FEV1/FVC ratios than the control group (P < 0.05), and the depressed group was significantly lower than that in the non-depressed group (P < 0.05). Pearson correlation analysis revealed that the standard deviation of normal R-R intervals, standard deviation of the mean of 5-minute normal R-R intervals, root mean square of successive differences of normal R-R intervals, percentage of normal R-R intervals greater than 50 ms, high-frequency, and low-frequency indices showed positive correlations with lung function parameters (P < 0.05) and negative correlations with BDI scores (P < 0.05).

CONCLUSION

Compared to patients without COPD, the incidence of depressive symptoms is higher among patients with COPD and is negatively correlated with the patients’ HRV indices. In contrast, HRV indices are positively correlated with the patients’ pulmonary function parameters. Patients and healthcare professionals should enhance their awareness of depression, actively conduct depression assessment screenings, and incorporate HRV indices into disease management. This approach aims to improve the psychological health of patients and ultimately enhance their prognosis and quality of life.

Keywords: Chronic obstructive pulmonary disease; Heart rate variability; Lung function; Depression; Beck depression inventory

Core Tip: Among 120 chronic obstructive pulmonary disease (COPD) patients, 35.8% (43/120) suffered from depression, compared to 5.0% (3/60) in the control group. Heart rate variability (HRV) indices, such as standard deviation of normal R-R intervals, standard deviation of the mean of 5-minute normal R-R intervals, root mean square of successive differences of normal R-R intervals, percentage of normal R-R intervals greater than 50 ms, high-frequency, and low-frequency were significantly lower in both depressed and non-depressed groups of COPD patients compared to controls (P < 0.05). Forced vital capacity (FVC), first-second expiratory volume (FEV1), and FEV1/FVC ratios were also significantly lower in both COPD patient groups compared to controls (P < 0.05). Pearson correlation analysis indicated positive correlations between HRV indices and lung function measures (P < 0.05) and negative correlations with Beck Depression Inventory scores (P < 0.05).