Evaluating Treatment Products, A Doctors' Perspective

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Medical Author: Dennis Lee, MD
Medical Editor: Melissa Conrad Stoppler, MD

• Why do doctors recommend some health products or measures but not others?
• How do doctors evaluate effectiveness and safety?
• What are doctors' limitations in evaluating products?
• What is an anecdote in medicine?
• What are the shortcomings of anecdotes in medicine?
• What is a placebo?
  • What is a placebo effect?
• What is an observational study?
• How do doctors recommend treatments for disease prevention?

Why do doctors recommend some health products or measures but not others?

Many of us are interested in taking steps to prevent diseases, stay healthy, and to preserve and improve our quality of life. But deciding what diets and nutritional products are best, and what medications to take is not easy. There are a bewildering number of nutritional products and medications that purportedly can prevent diseases and keep us healthy. While some of these products have proven safety and effectiveness, many have not been subjected to any scientific evaluation, and some are downright harmful. Increasingly, doctors are being asked to advise patients on how to prevent diseases. However, the medications and measures doctors recommend can be quite different from those recommended by nutritionists, chiropractors, complementary or alternative health providers, etc.. What is the reason for these differences? Why do doctors recommend some products but not others? How do doctors determine whether a product is good or bad? How good are doctors' recommendations? What are the doctors' weaknesses and limitations?

The process (steps) doctors commonly adopt in evaluating any disease prevention medication or product is imperfect. And the resultant doctors' recommendations are not always right (most of the recommendations in fact change over time as more scientific evidence becomes available). But the process itself is "honest"; it is there to minimize harm while trying to do some good.

How do doctors evaluate effectiveness and safety?

These are the questions doctors ask when evaluating a new health product, medication, treatment, or prevention measure:

1. Its effectiveness and safety have been demonstrated by prospective, double blind, randomized, placebo-controlled clinical trials? In prospective, double-blind, randomized, placebo-controlled trials, patients who are similar in age, sex, genetic background, and other characteristics such as health status, and diet are randomly assigned to receive either the test medication or a placebo. The study has to be conducted in a double blind fashion, meaning neither the patients nor the researchers (those who are administering the drug or treatment) know who is receiving the test medication or the placebo. At the end of the trial, treatment results from the medication-treated group are compared to the placebo-treated group to determine if the test medication is more effective than the placebo. Randomly assigning study subjects and double blinding of subjects and researchers are important to eliminate human bias from these trials. Comparing test medications to placebo eliminates the placebo effect (see below).

2. Its effectiveness and safety have been critically reviewed by independent experts? Independent experts (not affiliated with the company manufacturing the product or drug and who are not in a position to receive monetary gain from the product) need to critically review the trial design, methodology, results, and researchers' conclusions before the trial can be accepted for publication in a reputable medical journal.

3. Its effectiveness and safety have been validated by other researchers? Having the trial published in reputable journals is still not enough. Most doctors want to see validation (confirmation) of the trial results by several independent research teams. There is comfort in numbers.

4. How many subjects have been treated and for how long? Adverse side effects of medications or products may not show up until a large number of people have used the product over long periods of time.