“If we knew what it was we were doing, it would not be called research, would it?”
Medicine is still researching. Or are we practicing? Either way, we are in the era of evidence based medicine. The evidence is based on research and the research is often flawed or imperfect. In 2005, a Greek scientist examined the 45 most prominent studies with effective interventions published in medical journals since 1990 and found that about one-third of them were ultimately refuted. So those decisions that physicians based on the studies that were refuted, were ultimately found to be poor medical decisions. They seemed to be good decisions at the time.
Why were the studies refuted? Unfortunately, scientists lack the ability to measure all of the variables they want to measure. Sometimes, a variable that is easily measurable is studied in place of a variable that is more difficult to measure or can’t be measured. Other times, a variable with a rare occurrence may take too long to measure. An article from Discover Magazine details this,
“A bolt of excitement ran through the field of cardiology in the early 1980s when anti-arrhythmia drugs burst onto the scene. Researchers knew that heart-attack victims with steady heartbeats had the best odds of survival, so a medication that could tamp down irregularities seemed like a no-brainer. The drugs became the standard of care for heart-attack patients and were soon smoothing out heartbeats in intensive care wards across the United States.
“But in the early 1990s, cardiologists realized that the drugs were also doing something else: killing about 56,000 heart-attack patients a year. Yes, hearts were beating more regularly on the drugs than off, but their owners were, on average, one-third as likely to pull through. Cardiologists had been so focused on immediately measurable arrhythmias that they had overlooked the longer-term but far more important variable of death.”1
Sometimes the evidence is just lacking. Physicians may give advice based on small studies that may have been designed in a less than perfect manner because that is the only evidence that is available. As more evidence is created, advice changes to match the evidence.
Doctor, should a woman take hormone replacement after menopause to reduce coronary heart disease risk? Prior to the Women’s Health Initiative study the answer was yes. Then the Women’s Health Initiative study was begun to assess the change in cardiovascular risk associated with hormone replacement. The study was stopped early after an increase was found in the risk of stroke but no change in cardiovascular risk, the study’s main outcome measure. The study’s authors suggested that hormone therapy not be prescribed for the purpose of chronic disease prevention in postmenopausal women after this study showed that the risks outweigh the benefits.
Other notable recommendations have turned on a dime as well. Doctor, should I get a PSA test to screen for prostate cancer? The United States Preventive Services Task Force now says no you shouldn’t. Doctor, should I get a mammogram? Despite years of advising women to do so, a recent large study indicated that the death rate from breast cancer was the same between a group that received mammograms and one that didn’t. The advice that you receive from your doctor changes over time, even when you ask the same question every time.
It shouldn’t be surprising that medical advice changes. Our profession has a long history of treatments and behaviors that, in retrospect, were ill advised and changed after more information became available. In 1847, Ignaz Semmelweis suggested that the physicians in the Vienna General Hospital Obstetrical clinic were giving their patients a bacterial infection by going from autopsies to examining pregnant women without handwashing. This obstetrical clinic had an infection rate that was three times that of midwife clinic next door and this infection, puerperal fever, had a mortality rate of 10-35%. Dr. Semmelweis was laughed out of the local medical community for the suggestion that a doctor should wash his hands in between these activities. Years later Louis Pasteur found the bacterial cause of puerperal fever and Dr. Semmelweis was redeemed. These days we know to wash our hands in order to reduce the likelihood of spreading bacteria, although hospital administrators are still pulling their hair out attempting to get doctors to follow the rules.
More recently, our understanding of gastric ulcers has changed. Prior to the early 1980’s physicians cited their patient’s stress level or diet as the cause for the patient’s ulcer. It’s a time honored tradition in medicine to blame the patient when the physician doesn’t understand the cause of the disease and stress is a usual suspect. Bed rest and bland diets where the prescription of choice. Then, in the early 1980’s, H. Pylori bacteria were found to be cause of peptic ulcer disease and although conversion occurred slowly, treatment regimens with antibiotics now prevail.
These examples show that as medical science advances and provides more information the advice from your physician will change. What was thought to be true one day, may be disproved the next and your doctor’s advice will change just as quickly. This happens to the public as easily as it happens to physicians. The number of people texting and driving has reduced as awareness of it’s harms have been made public. Our behaviors change as the information that we have changes.
It’s expected that as we gain more knowledge about a subject our conclusions will change. The scientific method predicts this. One should form a hypothesis, test the hypothesis, draw conclusions and either form a new hypothesis if this one doesn’t work out or take the next step in the chain of events if the hypothesis proves true. However, we in medicine tend to become too dogmatic too soon about medical research. I think this is human nature. It’s much easier for physicians to explain health choices in a black and white manner as opposed to discussing the vagaries of cholesterol as it applies to heart attack risk. There are many reasons this may happen. Maybe the physician has a god complex and wants to seem above reproach, maybe the doctor doesn’t understand the nuances of the research and would have trouble explaining the gaps in our scientific knowledge, or maybe the doctor is only given 15 minutes for a visit and they think that it would just take too long to explain this information to the patient.
The cause for the black and white explanation should be less important to the patient than how certain their doctor is about the advice that is given. There are taxonomies to report the strength of a recommendation based on the quality of research. This is available to physicians and we should make this information available to patients. Patients should understand that when I make a recommendation based on research that has many large gaps in the knowledge base, it’s more likely that this recommendation will change in time versus a recommendation where the research is robust and consistent.
Recommendations with more uncertainty lead to more risk. When you add this risk to the known risk of a medication or a procedure it may be too much for a patient to accept.
So, doctor, if I can’t depend on all of your advice, maybe I should just look to supplements to help with my problems. It would be nice if this were the answer but, unfortunately, there are risks here as well. With pharmaceuticals there are certainly risks, but you can at least trust that most of the risks can be known before you take the pill. The FDA requires drug manufacturers to undergo compliance testing and the FDA takes pharmaceuticals from retails sites, distributors and manufacturing plants to test quality and safety.
Supplements are considered a food product by the FDA. As a food product, the FDA doesn’t require pre-market testing on supplements. The onus to assure safety of the product is on the company that makes the product. This seems ripe for conflicts of interest. Unfortunately, the great majority of over the counter supplements are not tested by third party companies for safety or efficacy.
In response to concerns about supplement contamination, product substitution, and decreasing consumer confidence scientists in Ontario, Canada published an article in BMC Medicine, in October of 2013, that shed light on the fact that many supplements tested were adulterated or contained none of the stated ingredients. The scientists used a scientific fingerprint, called DNA barcoding, to identify the plant based material in widely available supplements. Testing was done on 44 supplements from 12 different and unnamed companies.
Of the 44 herbal products, 32% were found to have NONE of the main product. You read that right, none. Other plant material was substituted instead of the product on the label. Fillers that were not listed on the label were found in products from 33% of the companies. The fillers were detected in one out of every five products tested. One of the fillers found was wheat. It’s already hard enough as it is for those with Celiac Disease or glutein sensitivity to navigate the processed food landscape, apparently supplement companies are not making it any easier for them.
In addition to not getting what you expect, some products packaged as supplements may put your health at risk. Fabaceae, which was substituted for St. John’s Wort in one bottle, is an herbal laxative and may cause diarrhea, abdominal pain or liver damage. Feverfew was found in two bottles labeled as Echinacea and in one other supplement. Feverfew has been used to treat fever, migraine and arthritis. However it also has negative side effects such as nausea, vomiting, abdominal pain, diarrhea, and flatulence; some users experienced withdrawal syndromes when discontinuing use, such as rebound headaches and muscle and joint pain. Feverfew reacts with some medications resulting in an increased risk of bleeding and it should never be taken by a pregnant woman.
Other examples exist of adulteration or substitution within herbal supplements. Many believe that even if these supplements don’t help, at least they can’t hurt. Unfortunately, this belief may prove false at times. Until more supplement companies verify their product through organizations like the United States Pharmacopeial Convention you cannot know what you are ingesting when you take a supplement.
I try to help my patients choose supplements they can trust by using consumerlab.com as a third party that can verify some supplements. However, this company doesn’t test all available supplements.
What’s the take home message for this long, rambling post? We cannot expect 100% certainty from just about anything in medicine. Recommendations change by the day as we adjust to new information. Pharmaceuticals, like the anti-arrhythmia medications referred to earlier may decrease the risk for one problem while increasing the risk for another and supplements have their own set unknowns that will, hopefully, be clarified as the supplement industry matures.
What can you count on? You can trust that if you live a healthier life with appropriate sleep, exercise, nutrition, an ounce of prevention, and joy, you can reduce your need for medical advice and, therefore, reduce your risk.
1. Why Scientific studies are so often wrong: The streetlight effect. Freedman, D. Discover Magazine. 12/10/10.