Relaxation Therapy for Hypertension: Design Effects and Treatment Effects2

Abstract The outcome literature on relaxation therapy for hypertension is surveyed and compared with the results of a recent meta-analysis, the Hypertension Intervention Pooling Project (HIPP). The results in the literature appear more favorable than those obtained in the HIPP. It seems that different impressions regarding the efficacy of relaxation therapy are reached depending on whether all studies or only methodologically sophisticated studies are examined. Besides pre-treatment pressure, the effect of baseline entry characteristics of a study were found to affect outcome: the largest declines in systolic pressure were reported in studies that included only one baseline session and used patients who were new to the outcome measurement setting. Comparing the changes of blood pressure in response to different treatment modalities yielded few differences once the effects of pre-treatment pressure and baseline entry characteristics had been considered; nevertheless, further research might be indicated to assess the effect of stress- or anxiety-management and EMG-biofeedback-assisted relaxation, using appropriate designs. The possibility of patient characteristics predisposing to successful treatment outcome was considered, but no clear findings are available at this time. A final concern is a possible lack of generalization of the relaxation effect outside of the blood pressure measurement situation; the declines in blood pressure observed with relaxation therapy may be transient and specific for the measurement situation.