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When Evidence-based Medicine Hits a Bias Roadblock

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At NatureMed, we believe every patient should receive evidence-based medicine. Evidence-based medicine is not meant to be a cookbook, but rather a bottom-up decision system that integrates the best available scientific evidence with the doctor’s clinical experience according to the patient’s circumstances and preferences. Patients in my practice receive evidence-based natural medicine. I am resistant to implementing treatments that do not have a reasonable amount of human data supporting them.

Too often, conventional doctors use the term evidence-based medicine to describe what they have been taught to do. The assumption is that if there was good scientific evidence, they would have been taught about it. In other words, if they were not taught about it there is no evidence. Medicine has become more systematic and industrialized with prescribed standards of care which do not allow for lateral thinking.

What is Evidence-based Medicine?

According to the National Cancer Institute, the definition of evidence-based medicine is:

“A systematic approach to medicine in which doctors and other health care professionals use the best available scientific evidence from clinical research to help make decisions about the care of individual patients. A physician’s clinical experience and the patient’s values and preferences are also important in the process of using the evidence to make decisions. The use of evidence-based medicine may help plan the best treatment and improve quality of care and patient outcomes.”

What I found very interesting about this definition is the part about the patient’s values and preferences. I have never seen this implemented. A classic example is when the patient wants to use a nutritional supplement or particular diet to treat a condition. The problem here is doctors not trained in this and they assume there is no evidence. In many cases the doctor-patient relationship suffers as a result. Responses such as, “none of that stuff works” or, “I want you to stop all your supplements” are too dismissive and patients end up feeling like they are not getting personalized care as a result.

In defense of conventional doctors, they are not trained in this, have very limited time, and are constrained by what they can do. Never blame the doctor, just the system. Conventional doctors are trained in hospitals with a less healthy patient population and are just trying to do the best job they can.

Just because there is no evidence does not mean something does not work. Alternative, naturopathic, complementary, alternative, integrative, and functional medicine all suffer from this.

The Issues with Efficacy Data

Meta analyses and systematic reviews are the typical sources of data used to determine efficacy of a particular treatment. The problem with these big review studies is that sometimes the criteria for inclusion can limit the studies that are included. For example, a meta-analysis may only allow double-blind placebo controlled studies with a minimum of 150 patients.  Anything else is not included in the review whether it is positive or negative.

When doing a review on a drug, for instance, small sample size is not an issue because drug studies are typically funded by multimillion dollar drug companies along with money from academic institutions and governmental bodies such as the National Institutes of Health.

Studies on natural substances tend to be smaller, shorter and sometimes not double-blind placebo controlled because of cost.

The end result can be an inclusion bias, or simply no recommendation, because more evidence is needed. This is quite common when looking at nutritional supplements with good animal and human data. Often there just need to be more published studies with a larger number of patients to reach the point where a positive recommendation is mentioned in the conclusion.   Typically, at the end of the conclusion on these articles it will say something about the data being promising but more evidence is needed.

Evidence-based medicine can be restrictive, reductionistic, and simplistic even when the data is good. A clinician should be able to think outside the box. By following rigid guidelines modern medicine does take on similarities to a cookbook approach. Good doctors do not practice cookbook medicine.

We all want the best treatments and procedures but want that information without bias.

The Caveat of Evidence-based Medicine

A March 2022 article in the British Medical Journal provides a dismal opinion regarding the validity of evidence-based medicine. In this article entitled “The Illusion of Evidence-based Medicine the following key points are made:

  • The paradigm of evidence-based medicine relies on data from clinical trials, most of which are conducted by the pharmaceutical industry.
  • Confidential pharmaceutical industry documents released by court order (many examples) have provided an unsavory insight into how industry sponsored clinical trials are misrepresented.
  • Scientific progress has been slowed by the ownership of data and the suppression of negative trial results including failure to report adverse events. Medicine is largely dominated by a small number of pharmaceutical companies that compete for market share so there is no incentive to share the raw data.
  • In the face of inadequate government funding, many universities have become instruments of industry and agents for the promotion of commercial products.
  • Regulators receive funding from the pharmaceutical industry and use these industry funded trials to approve drugs, in many cases without seeing the raw data. A revolving door exists whereby regulators work for pharmaceutical companies and then back as regulators, and vice versa.

Let’s use an example from my preventive cardiology clinical practice. Extensive high-quality evidence supports the role of diet, nutrition, exercise, stress management, and sleep in the prevention and treatment of coronary artery disease. The evidence is there but it’s not implemented. There are specific cholesterol-lowering foods and nutraceuticals that may be used before prescriptions but there is no knowledge and it’s not implemented. One of the main reasons I am busy is that patients want to try a natural approach first and then try the prescription route only if the natural approach does not work.

In summary, there should be as much evidence-based medicine implemented as possible, but one needs to be careful about bias.

Conventional doctors are trained in the use of prescription drugs to treat patients and unfortunately evidence-based medicine is really only looking at prescription drugs. The definition of evidence-based medicine that is described on the National Cancer Institute website specifically says that evidence-based medicine should include the experience of the practitioner as well as the values and circumstances of the patient. Too often, medicine is delivered as cookbook and protocol-based with no time to get into discussions or alternative, natural and complementary treatments.

We should look at all evidence and think holistically about the patient. The insurance companies are largely responsible for dictating what doctors can do. Conventional doctors should not assume that just because they were not taught about it that there is no evidence.

Learn more about Dr. Steve Parcell’s evidence-based medicine approach, or contact our office to schedule a visit: 303-884-7557.


Jureidini J, McHenry LB. The illusion of evidence based medicine. BMJ. 2022 Mar 16;376:o702. doi: 10.1136/bmj.o702. PMID: 35296456.