Research: PLAUGHER and colleagues,

Listed in Issue 82


PLAUGHER and colleagues, Director of Research, Life Chiropractic College West, 25001 Industrial Boulevard, Hayward, California 94545, USA, examined the feasibility of carrying out a randomized controlled clinical trial of short- and long-term effects of chiropractic treatments given in the private practice setting to patients with high blood pressure compared with brief soft tissue massage or non-treatment.



This feasibility study was conducted in a private practice out-patient chiropractic clinic. It was a randomized, controlled, comparative trial involving three parallel groups of subjects. Subjects were 23 patients aged 24-50 years with systolic or diastolic essential hypertension. The chiropractic group received 2 months of full-spine chiropractic care (i.e. Gonstead) involving mainly specific contact, short-lever-arm adjustments to motion segments that showed signs of subluxation. The massage group received brief effleurage at localized areas of the spine believed to be showing signs of subluxation. The control group rested alone for about 5 minutes in an adjustment room during study treatment sessions. The investigators recorded the cost per enrolled subject and measured systolic and diastolic blood pressure (BP) using a random-0 sphygmomanometer and patient-reported health status (using SF-36). They also assessed subjects’ cooperation with the randomization procedures and measured drop-out rates, recruitment effectiveness, temporal stability of BPs at the start of the study and the influences of the inclusion and exclusion criteria on the subject pool.


30 subjects enrolled. One was later deemed to be ineligible and six subjects dropped out during the study. Cost per subject enrolled was US$161. All subjects in the chiropractic and massage therapy groups were classified as either overweight or obese, whereas only two were classified thus in the control group. Patient-reported health status (SF-36 profile) was similar to that of a normal population for all three experimental groups. Mean changes in diastolic BP were as follows: chiropractic group, -4; brief massage group, 0.5; control group, -4.9. At the end of the study, mean changes in diastolic BP were as follows: chiropractic group, -6.3; brief massage group, -1.0; control group, -7.2 Mean improvements in the chiropractic and control groups remained consistent over the follow-up period.


This pilot/feasibility study uncovered a number of issues needing to be addressed before proceeding to a full-scale clinical trial. Recruitment may require a multidisciplinary approach to identify sufficient numbers of suitable patients with hypertension who are not taking medication to control their condition. Methods to ensure comparable treatment groups with regard to prognostic variables (e.g. weight) need to be implemented. The findings of this study, however, indicate that it is feasible to conduct a full-scale, three-group, randomized clinical trial in the private practice setting to investigate the effects of chiropractic adjustments.


Plaugher G et al. Practice-based randomized controlled-comparison clinical trial of chiropractic adjustments and brief massage treatment at sites of subluxation in subjects with essential hypertension: pilot study. Journal of Manipulative and Physiological Therapeutics 25 (4): 221-39. May 2002.


The above research study (which was actually a feasibility study prior to conducting a fully-fledged clinical trial) demonstrates the myriad of details which have to be considered and implemented in designing a truly randomized clinical trial in which all groups of patients are as equal as possible, so that one or more treatment groups don’t turn out to be obese or overweight and the control group of normal weight.

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