December 2006

The numbers game in research

by Dr. Matthew McCoy

An original research report published in the Journal of Vertebral Subluxation Research (JVSR) last month provided support for the hypothesis that a positive relationship exists between a correction of the occipitoatlantoaxial subluxation complex and a reduction in depressive symptoms in some people.

Researchers used the Beck Depression Inventory II (BDI‑II) survey to measure subject's level of depression. This 21‑item self‑reporting instrument is one of the most widely used psychological measures and is considered standard in many clinics and hospitals for establishing clinical depression.

All subjects were determined to be clinically depressed and had an upper cervical subluxation and took the BDI‑II test before and after receiving chiropractic adjustments (Grostic technique). The mean score on the BDI‑II for the participants before the chiropractic intervention was 17, and after the intervention it was eight. Nearly three‑quarters (73.3%) of all research subjects tested showed a marked improvement after chiropractic care.

While not conclusive, the research indicates a strong possibility that chiropractic adjustments to correct upper cervical subluxations could help millions of people now suffering from the devastating effects of depression.

The research involved 15 patients in three different offices.

What's your reaction to that news? Did you get excited until you came to the last sentence?

Like many people, you might be tempted to shrug off this research because of the relatively small number of subjects. Yet, small samples are used in medical research all the time and most "Phase I" research projects involve fewer than 50‑80 subjects. Drug companies conduct Phase I research to test the toxicity of new drugs to humans and often make announcements of their positive results after testing on only a handful of subjects.

For instance, Neurologix released a "news flash" this October announcing that it had "successfully completed its landmark Phase I trial of gene therapy for Parkinson's disease with statistically significant results." The data was presented at the 36th Annual Meeting of the Society of Neuroscience in Atlanta and was used to hype company stock to investors. The trial involved 12 subjects.

A study on the effects of progesterone treatment for cocaine users, reported in the journal  Pharmacology Biochemistry & Behavior, involved 10 subjects. And research published in Gerontology on the drug rivastigmine involved a mere eight subjects.

Obviously, when it comes to medical research, significant results can be obtained with small samples. But this involves only Phase I research ‑‑ preliminary studies that hint at the possible effect of a treatment on a larger population. Next come Phase II and Phase III (and even Phase IV) trials that begin to more deeply explore and confirm the results of the Phase I project.

This is where chiropractic research is weakest. While some retrospective literature reviews are on large numbers of patients, few of our clinical studies involve more than 100 people, which still puts it in the Phase I category. A much‑cited project on chiropractic and autism, published in Clinical Chiropractic, had 26 subjects. Another, published in of Manipulative & Physiological Therapeutics on chronic spinal pain syndromes had 77 patients. A few studies on back pain manage to encompass a larger sample, but they serve more to limit chiropractors than to support their position in the health and wellness arena.

Let's get back to the chiropractic and depression study for a minute. What would your reaction have been if the research had been conducted on 500 people, with the same results? What if 730 out of 1,000 subjects had shown significant improvement, or 7,300 out of 10,000?

These are the kinds of numbers we need to look at if we're going to reach definite conclusions about the effect of subluxation on health ‑‑ and the benefits of chiropractic adjustments.

Recruiting and compiling data on that many subjects is a massive task. Even the larger drug companies and medical research institutes rarely manage to conduct that type of research and when they do, they rely on huge government grants. This February, for example, the UK Biobank, a £ 61 million government‑backed project to study how certain diseases develop, began recruiting the first of its eventual goal of 500,000 subjects. The NAAR Autism Genome Project, considered the largest study of its kind ever conducted, analyzed 6,000 samples of DNA from 1,500 families.

RCS (Research & Clinical Science) is the only chiropractic research group to conduct large‑scale studies on the effect of chiropractic on various aspects of health and wellness. The SRQOL survey used in the RCS research incorporates the SF‑36 Health Survey, a standard quality‑of‑life test developed by the RAND Corporation and extensively administered and validated. The test measures four key elements of wellness: physical health, emotional well‑being, stress level, and life enjoyment level. RCS will compare "before and after" survey results to pinpoint the effects of chiropractic care.

Most impressive is the fact that RCS will collect data from hundreds of thousands of subjects during its long‑term research project. No one, not even our most virulent critics, will be able to shrug off the results.

No one can deny the value of small scale, Phase I studies. When 75% of the subjects in any research show significant improvement after chiropractic, it's important knowledge to gain. It's the first step toward demonstrating the wide‑ranging benefits of chiropractic care on the human body. But, thanks to RCS and the hundreds of field chiropractors willing to become RCS Authorized Clinical Investigators, we're taking the second step and testing chiropractic on a large segment of the population. For more information on participating in this research effort, contact RCS at 1‑888‑712‑2326.

(Dr. Matthew McCoy is one of the founding members of the Council on Chiropractic Practice and has been instrumental in the development of the profession's most widely accepted set of chiropractic guidelines. He's also editor of the Journal of Vertebral Subluxation Research and has extensive practice, research and educational experience. He gained international acclaim when he helped introduce chiropractic to the Russian medical community by developing a chiropractic spine treatment, teaching & research center in Vladivostok, Russia. He is currently the Director of Research at Life University. Dr. McCoy is Vice‑President of RCS, serves as a member of the WCA Board of Directors, chairs the WCA Chiropractic Advocacy Council and was a liaison member of the National Academy of Sciences and Institute of Medicine's Committee on Alternative Medicine. He can be contacted via e‑mail at editor@jvsr.com)