A meta-analysis on heart rate variability biofeedback and depressive symptoms

Abstract

Heart rate variability biofeedback (HRVB) has been used for a number of years to treat depressive symptoms, a common mental health issue, which is often comorbid with other psychopathological and medical conditions. The aim of the present meta-analysis is to test whether and to what extent HRVB is effective in reducing depressive symptoms in adult patients. We conducted a literature search on Pubmed, ProQuest, Ovid PsycInfo, and Embase up to October 2020, and identified 721 studies. Fourteen studies were included in the meta-analysis. Three meta-regressions were also performed to further test whether publication year, the questionnaire used to assess depressive symptoms, or the interval of time between T0 and T1 moderated the effect of HRVB. Overall, we analysed 14 RCTs with a total of 794 participants. The random effect analysis yielded a medium mean effect size g = 0.38 [95% CI = 0.16, 0.60; 95% PI = - 0.19, 0.96], z = 3.44, p = 0.0006. The total heterogeneity was significant, Q_T = 23.49, p = 0.03, I² = 45%, which suggested a moderate variance among the included studies. The year of publication (χ²(1) = 4.08, p = 0.04) and the questionnaire used to assess symptoms (χ²(4) = 12.65, p = 0.01) significantly moderated the effect of the interventions and reduced heterogeneity. Overall, results showed that HRVB improves depressive symptoms in several psychophysiological conditions in adult samples and should be considered as a valid technique to increase psychological well-being.

Figure 1

Flowchart illustrating study selection, review strategy and data extraction.

Figure 2

Risk of bias assessment. Low risk of bias is represented with green dots, high risk of bias in red, unclear risk of bias in yellow.

Figure 3

Forest plot, each square corresponds to one study and the lines represent 95% confidence interval. The size of each square represents the weight of the study. The diamond at the bottom represents the cumulative effect size with 95% confidence interval. Higher positive values indicate greater effect of the HRVB intervention compared with the control group.

Figure 4

Funnel plot. Black dots represent studies included in the present meta-analysis. The vertical line represents the effect size.

Figure 5

Plot illustrating the relationship between year of publication and cumulative effect sizes. In particular, the most recent the study, the greater the effect size. The area of the points is proportional to study variances. Three studies published in 2020 are not reported due to overlapping positions. Dashed lines indicate 95% CI, the dotted line indicate Hedges' g = 0 (i.e., no difference between groups).