Ever gotten the flu shot, then caught the flu? Know someone who refused to vaccinate her kids, fearing it causes autism? Heard accusations of doctors of over-prescribing to get pharmaceutical kick-backs? Are any of these concerns valid? How can you know whose advice to listen to when it comes to your family’s health?
Recently, a friend sent me a link to an online Jewish publication that vilified the use of statin medications in lowering cholesterol, advocating replacing them with exercise and alternative treatments. The author told the story of a patient who became paralyzed after taking a statin, concluding that the medication caused the condition. He argued his point using misinformation, partial truths, conspiracy theories, and misunderstood physiology.
Reading the article, I was horrified. What if patients with coronary disease believe this author and take his advice? This author could be responsible for people’s worsening illness or even their deaths.
Lately, claims opposing traditional medical treatment have been gaining popularity, and the resulting controversy has risen to the forefront in light of current community health crises like the measles epidemics in Monsey and Israel. Clearly, misunderstanding the facts and the fictions of medical recommendations can be dangerous. But how do we tell what’s true and what’s false, what’s safe and what’s harmful? And how do we trust our doctors’ recommendations when they seem to change from year to year?
To better assess who to believe, let us look at the various types of evidence used to back up different recommendations, and analyze their strength and validity.
The weakest type of evidence is the anecdote. These proofs typically begin with the phrase, “I know a guy,” then go on to tell the story of someone who listened to a medical recommendation and had a bad outcome. This type of evidence is completely unreliable because it doesn’t represent the vast majority of cases. If enough people do anything, something bad will occasionally happen to someone. But can you imagine giving up shopping because you heard about someone dying in a car accident on the way to the grocery store? This kind of evidence should never be used to make serious medical decisions, and it is not a component of any real medical research. But it seems to be disturbingly effective in convincing people that certain treatments are illegitimate.
The next weakest type of study is the retrospective review, where researchers analyze records or questionnaires, looking for a correlation between something done in the past and some outcome. The problem is, even if two factors seem associated, it doesn’t prove cause and effect. If you ask a group of people if they eat their vegetables and then ask if they exercise, you may find a high correlation between the two actions. You might then conclude that eating vegetables causes people to exercise, when the truth is really that people who are health conscious tend to do both. This type of study is frequently reported as “evidence” for fads that last for a few years, only to be disproved later by better studies. They are occasionally used to make medical recommendations, and are usually responsible when those recommendations are subsequently reversed.
The best kinds of studies are known as prospective, double-blinded, placebo-controlled studies. In these, pills are numbered and patients randomized, so only a third party knows which is the real medication and which is the placebo. Neither doctors nor patients know what each patient is getting. Larger studies are more powerful and less likely to be later proven incorrect. The very best of these studies show the effects on mortality (death) or morbidity (illness), rather than just the effects on some factor (like cholesterol or blood pressure), which may or may not affect ultimate patient survival. A large prospective, double-blinded study that shows a reduction in death rate is the most reliable and the most difficult to argue against, even for the most motivated conspiracy theorists.
When medical associations create guidelines, they grade each recommendation based on the strength of the supporting studies and the expected level of benefit to the patient. To get the highest grade, a recommendation must be based on multiple large, strong, prospective studies that show consistent results, and the demonstrated benefit to patient health must be significant. Thus, the higher the grade, the less likely the recommendation is to change in the future.
So when you see an article arguing against the standard of care, make sure to look deeper into the type of evidence the author uses to support his or her view. Be wary of faulty arguments suggesting that “natural” is necessarily better, or that if something is necessary for the body to function, too much of that thing is not problematic. If you have questions, talk with your doctor, and he or she can explain the relevant recommendations and the strength of the research behind them.
The following are some of the stronger current recommendations for adults:
- Statins for patients with coronary artery disease (Grade 1A, the highest grade) have been shown in multiple large, double-blinded, placebo controlled trials to lower the risk of a second heart attack or stroke by about one third!
- Flu shots, especially for the elderly, chronically ill, or fragile, have been shown to reduce heart attacks and strokes in the elderly, as well as flu-related deaths. Pneumonia shots for patients over 65 and at high risk for pneumonia have been shown to be helpful as well.
- Colonoscopies are recommended for everyone between 50 and 75 (Grade A recommendation). Unlike mammograms and PSA tests, which try to detect early cancers, a colonoscopy detects pre-cancerous polyps and removes them before they become cancers. Colon cancer is the third most common type of cancer, and this is one of the few ways to actually prevent it.
- Cervical cancer screening is recommended every three years for women aged 21 to 29 and every three to five years for women aged 30 to 65 (Grade A recommendation).
- Mammograms are recommended for women over age 40 every one to two years (only a Grade B recommendation).
- The new shingles vaccine, Shingrix, is recommended for everyone over the age of 50. While not 100% protective, it does protect over 90%, and although shingles is generally not fatal, it can be very painful.
There are many other recommendations for specific situations that are not included here, but you can consult with your physician for all the current guidelines.
