The effects of biofeedback for the treatment of essential hypertension: a systematic review.

OBJECTIVES To assess the evidence for the long-term effectiveness of biofeedback for the treatment of essential hypertension in adults and to model any clinical benefits. DATA SOURCES Bibliographic databases including the Cochrane Library, EMBASE, MEDLINE, ISI Web of Knowledge/Web of Science, ISI Web of Knowledge/ISI Proceedings, the Cochrane Library 2007, CINAHL, AMED and PsycINFO were searched up to May 2007. REVIEW METHODS A systematic review following accepted guidelines was conducted. Randomised controlled trials (RCTs) that compared biofeedback procedures with antihypertensive medication, placebo (sham biofeedback treatment), no intervention or other behavioural treatments were included. The outcome measure was change in blood pressure. RESULTS A total of 927 non-duplicate references were identified by the search strategy and subsequently screened for inclusion in the review. From these, 41 publications (including three abstracts) reporting 36 RCTs with a total population of 1660 treated patients met the inclusion criteria of the review. Twenty-one trials employed biofeedback treatment with no adjunctive therapy and 15 trials used biofeedback treatment alongside another treatment. The majority of trials were small with no post-treatment follow-up or follow-up of less than 6 months. The poor quality of the trials, differences in interventions and inconsistencies in the measurement of outcomes meant that it was inappropriate to pool data across studies. A narrative summary of the data based on trial author conclusions is presented. No studies reported long-term (> 12 months) follow-up of patients. Data were grouped first by treatment type and then by comparator. Trial results were variable and conflicting, demonstrating no consistent benefits of biofeedback in relation to moderation of hypertension. The lack of evidence of clinical effectiveness negated the need to conduct an economic analysis. CONCLUSIONS No evidence was found that consistently demonstrated the effectiveness of any particular biofeedback treatment in the control of essential hypertension when compared with pharmacotherapy, placebo (sham biofeedback treatment), no intervention or other behavioural treatments. Given the current standards for the treatment of hypertension, further research is likely to be considered only as an adjunct to pharmacological interventions.