HTN: Medical Nutrition Therapy (2015)


Goertz CH, Grimm RH, Svendsen K, Grandits G. Treatment of Hypertension with Alternative Therapies (THAT) Study: A randomized clinical trial. Journal of Hypertension. 2002; 20(10); 2063-2068.

PubMed ID: 12359986
Study Design:
Randomized clinical trial.
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To examine the effect of spinal manipulation on blood pressure.

Inclusion Criteria:
  • High-normal blood pressure or stage I hypertension diagnosed according to JNC-V guidelines: Participants with diastolic blood pressure (DBP) of 85 to 99mm Hg and systolic blood pressure (SBP) below 160mm Hg were eligible 
  • Men and women aged 25 to 60 years.
Exclusion Criteria:
  • Taking more than one type of antihypertensive medication
  • History of life-limiting health conditions or contraindications to chiropractic spinal manipulation
  • Change in treatment for high blood pressure within the previous three months
  • Receiving chiropractic spinal manipulation within the last six months
  • History of severe mental illness
  • Drinking more than an average of four alcoholic drinks per day
  • Actively trying to lose weight
  • Not willing to fully participate in both treatment groups
  • Patients reporting average pain levels of five or above on a 10-point visual analog-type scale.
Description of Study Protocol:


Participants were recruited using newspaper and radio advertisements, tear-off posters and brochures distributed in public places and postcard mailings to Twin City metro area residents who met the age criteria based on a mailing list obtained from the Minnesota Department of Transportation. In addition, brochures describing the study were mailed to University of Minnesota faculty and staff.


Randomized clinical trial. A set of sealed, numbered opaque envelopes that contained the treatment group assignments was prepared and placed in random order.

Blinding Used

Blood pressure observers were blinded to treatment group. 


  • Dietary intervention program administered by a registered dietitian or a dietary intervention program administered by a doctor of chiropractic in conjunction with chiropractic spinal manipulation
  • Chiropractic treatments were administered by chiropractic physicians within private practice settings
  • Frequency of treatment for both groups was three times per week for four weeks, for a total of 12 visits
  • Time spent per visit was 15 to 20 minutes and was the same for both groups
  • Dietitian and Doctor of Chiropractic provided participants with written instructions on how to modify the diet; they were also given diet sheets, which included low-fat, low-salt recipes
  • Physical activity diaries.

Statistical Analysis

  • Sample size was estimated based on a two-sample T-test using average change in diastolic blood pressure over four weeks of treatment as the primary endpoint
  • Analysis was carried out by intention to treat
  • Baseline factors potentially affecting blood pressure were compared between groups using T-test and chi-square tests
  • Variables included were blood pressure, weight, age, race, sodium intake, alcohol consumption, pain levels, general health status and blood pressure medication status
  • ANOVA was used to compare pre-post change in variables of interest, including weight, alcohol consumption and physical activity scores as well as changes in blood pressure between groups.
Data Collection Summary:

Timing of Measurements

Endpoint measures were carried out after four weeks of treatment.

Dependent Variables

  • Systolic and diastolic blood pressure were measured with sphygmomanometer
  • Weight measured with shoes off on calibrated scales.

Independent Variables

  • Dietary intervention program administered by a dietitian or a dietary intervention program administered by a doctor of chiropractic in conjunction with chiropractic spinal manipulation
  • Compliance with dietary advice was monitored through average change in weight and the use of pre-post questionnaires to determine change in alcohol consumption and use of salt at the table or while cooking 
  • Physical activity diaries.

Control Variables

  • Weight
  • Age
  • Race
  • Sodium intake
  • Alcohol consumption
  • Pain levels
  • General health status
  • Blood pressure medication status.
Description of Actual Data Sample:
  • Initial N: 140 men and women, completed three eligibility visits and were enrolled. 69 in diet alone and 71 in chiropractic spinal manipulation
  • Attrition (final N): 128 completed the study (91%), 62 in diet alone and 66 in chiropractic spinal manipulation
  • Age: Mean 47.6±6.6 years in diet alone, 47.5±7.2 years in chiropractic spinal manipulation
  • Ethnicity: 8.8% African Americans in diet alone, 8.5% African Americans in chiropractic spinal manipulation
  • Anthropometrics: Study groups were comparable at baseline with no significant differences. Diet group weighed more than the chiropractic group (200 vs. 187 lbs, P=0.06).
  • Location: Minnesota.
Summary of Results:



Diet Alone Group (N=62)

Chiropractic Spinal Manipulation Group (N=66) Pre-Post Difference Between Groups P-value

Change in alcohol (beverages/week)

-0.1±1.5 -0.1±3.8 0 0.96
Change in weight (lbs) -0.8±4.5 -0.8±3.9 0 0.95
Change in BMI -0.1±0.7 -0.1±0.6 0 0.93
Use salt when cooking (%, yes) 90.3 83.1 7 0.23
Use salt at table (%, yes) 59.7 64.6 4.9 0.57
Physical activity (average total points) 860 889 29 0.90
Change in DBP (mm Hg) -5.6 -4.0 1.6 0.08

Change in SBP (mm Hg)





Other Findings

Changes in potentially confounding covariates did not differ between groups.

Average decreases in systolic and diastolic blood pressure were -4.9 over 5.6mm Hg for diet group and -3.5 over 4.0mm Hg for the chiropractic group.

Between groups, changes were not statistically significant, but a somewhat larger reduction was observed for participants in the diet alone group.

Over the course of the study, there was very little change in self-reported alcohol consumption in both groups.

Author Conclusion:

We conclude that community-based chiropractic spinal manipulation itself does not appear to have a role in the management of high blood pressure.

Funding Source:
Reviewer Comments:

Authors note the following limitations:

  • Lack of no-treatment control group
  • Study group limited in age and blood pressure range.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) ???
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes