THE EFFECT OF BIOFEEDBACK ON HYPERTENSION AND DIABETES: PRELIMINARY RESULTS FROM A SYSTEMATIC REVIEW

Abstract

Biofeedback is a mind-body intervention that uses a device to provide feedback on physiological responses, such as heart rate variability. Through training and practice, participants can learn to exert an element of control over autonomic responses. There is a wealth of research on biofeedback in a range of health conditions, this review focuses on hypertension and diabetes.The systematic review aimed to evaluate the effectiveness of biofeedback on systolic and diastolic blood pressure and psychological wellbeing in patients with hypertension and/or diabetes. The review was preregistered on PROSPERO and followed the PICO search strategy. The following databases were searched: MEDLINE, PsycINFO, CINHAL, PubMed, Embase and Cochrane Central Register of Controlled Trials. Selection criteria included randomised control trials, diagnosis of hypertension/diabetes, inclusion of pre and post intervention measurements and recordings of blood pressure, Hba1c or blood glucose.A total of 1189 papers were retrieved, 32 papers met the inclusion criteria. Sample sizes ranged from 10 to 301 with a total of 1425 participants, 48% female and mean age 50.16 (±8.16) and 48.71 (±9.19) in experimental and control group respectively. Of the 32 papers, 28 investigated hypertension and 4 papers looked at diabetes. Of the 28 hypertension studies, 13 showed significant findings in favour of biofeedback. The analysis excluded 11 papers due to incomplete data. Biofeedback was significantly associated with reduced systolic blood pressure (-3.62 mmHg, [-6.33, -0.90], p value < 0.0001; Figure 1) and diastolic blood pressure (-4.15 mmHg, [-6.04, -2.26], p value < 0.0001). Biofeedback modalities included galvanic skin response, heart rate variability, thermal, electromyography, blood pressure and heart rate. Intervention length ranged from 10 days to 4 months, and follow up ranged from 1 week to 12 months. Of the 4 diabetes papers, 2 showed significant findings in favour of biofeedback. A total of 7 papers recorded psychological wellbeing measurements (i.e. depression and anxiety). However, only two reported incorporation of psychological/wellbeing targeted intervention components.The preliminary findings highlight the high heterogeneity between existing trials in biofeedback modality, intervention length, follow up and details reported. The results show biofeedback had a significant effect on systolic and diastolic blood pressure. There is limited research on biofeedback and diabetes. This systematic review will inform the protocol development of a biofeedback feasibility trial in patients with hypertension and anxiety. A key finding is the limited use of psychological wellbeing based intervention components, despite study measurements and correlating hypotheses. This is an important element we will integrate within our biofeedback intervention.