Where is the Evidence? Before jumping out of an airplane with a parachute, it’s reassuring to have evidence that it’s safe. As it happens, parachuting is about 24 times safer than driving a car 10,000 miles. Who would have guessed? When it comes to health, you will be happy to know that jumping from planes isn’t one of my recommendations. However, when I do have a recommendation, you can be sure that it has an upside benefit that far outweighs the potential risk based on the available evidence. Surgeries of all types have a risk that is higher than driving a car but are often found to be acceptable treatments in view of the alternatives. The goal is to choose a treatment with the minimum risk and the best possible outcome. In most cases, medical evidence comes from studies that have been observed in thousands and sometimes millions of people. Often this evidence is in conflict with beliefs. One of my greatest challenges is overcoming misinformation about vaccines that patients have seen in newspapers, magazines, advertisements, or on the internet. Granted, not all types of evidence are simple to interpret or overwhelmingly convincing. For example, an expert opinion is nice but sometimes based on a small number of experiences. In contrast, evidence from studies that involve randomized subjects usually provides the highest quality evidence. In the case of vaccines, randomized studies that involve large numbers of people are possible. Hence the evidence for vaccines is very good. Of course, studies are no better than the assumptions they are based on. In the case of flu viruses, their ability to mutate and create new strains can, in some years, make the vaccines less effective than expected. In all studies, there is a chance that a possible outlier event has not been considered. In large studies, this chance may be estimated to be very small. A metaphor that describes these outliers (unexpected events) is the black swan. The metaphor is based on an ancient saying that presumed black swans did not exist. Despite ‘common wisdom’ a black swan was eventually discovered. In the case of experimental studies, rare events that are beyond the realm of normal expectations are always a possibility. Although not always welcomed, these events inevitably have the effect of bringing existing beliefs into question. As an example of belief in conflict with evidence, a Mayo Clinic study reported that up to 94% of patients who self-report penicillin allergy actually test negative for the allergy. That's an unfortunate belief given that it limits options when treating conditions such as methicillin-sensitive Staphylococcus aureus or Clostridium difficile. Gun ownership is a politically charged issue, with health ramifications. For a doctor, it’s hard to ignore evidence that American children are more than 80 times more likely to die from gun homicide than their peers in other countries. I will leave to you the value of gun ownership in your personal situation. As a doctor, I look at the evidence and the evidence shows a strong correlation between gun ownership and poor health outcomes. No doubt you have read about studies showing evidence that a glass of wine provides health benefits. Interestingly, a glass of grape juice provides more health benefits than wine and grapes are an even healthier choice than grape juice. Unfortunately, the limited evidence most hear is what the food distributor wants you to hear. So, if the sales pitch is for wine, guess which story you hear? While minimizing alcohol is recommended for best nutrition and in particular for weight loss, I must admit, I do enjoy a glass of wine with my husband before dinner. The evidence for aspirin had an off year. A recent study in The New England Journal of Medicine found that aspirin did not provide significant improvements in outcomes related to cardiovascular disease (CVD) or all-cause mortality, and it may cause worse outcomes related to cancer and hemorrhage. Studies published in The Lancet and The New England Journal of Medicine found aspirin to be of no benefit in primary prevention of cardiovascular events in certain patient populations. For now, these studies remain controversial until repeated by others. In medicine, one study rarely stands as strong evidence. Only after a study has been repeated many times with many different populations does it become strong evidence. For now, both AAFP and USPSTF maintain a recommendation for the use of aspirin as primary prevention in adults aged 50-59 who are at an increased risk for CVD and a low risk of bleeding. As your doctor, I follow the science as it evolves and offer revised opinions when the evidence is compelling. Strong evidence shows that what we eat plays a major role in determining our health. Despite the evidence, one in three U.S. adults has excess weight and suffers from nonalcoholic fatty liver disease. Many studies show that a lack of nutrition education is at the heart of the problem. As an example, a study in Nutrition found that patients who consumed 35 grams of fiber a day and limited protein to 0.8 grams a day per kilogram of body weight lost an average of 4.4 pounds in 12 weeks. Unfortunately, few realize that the best evidence for meeting these goals would be a plant-based whole foods diet. What other evidence might surprise you? Well, a review of 16 studies linked fast food to asthma. In contrast with what gets advertised, that makes fast food a very unhappy meal. As another example, the evidence shows that adolescents and young adults who survived initial self-harm are at significantly elevated risk for suicide and need follow-up care. After an attempt at self- harm, returning for regular visits with their doctor is important. Often the doctor is the adult figure that prevents them from a second attempt. Unfortunately, few primary care doctors are compensated for mental health issues. Alas, the evidence doesn’t always change the system. One in three people develops the viral infection called shingles in their lifetime. If over age 50, that should be a concern. Complications from shingles can include neuralgia, skin infections, organ failure, and vision loss. Fortunately, the vaccine has proven to be 97 percent effective in patients aged 50-69 for up to four years after vaccination. That’s impressive evidence. Still, beliefs often stand in the way and cause many to reject vaccinations that improve the odds for a healthy life. Staying abreast of the evidence in a world of change is challenging. As a Family Practice doctor that requires recertifying more often than any other medical specialty. Maintaining dual certifications in Lifestyle Medicine and Family Medicine adds to that challenge. In fairness, it’s a challenge I am happy to take on if it helps me provide you with the best care. Nancy Neighbors, MD Huntsville, Alabama Today's Family Physician The One Doctor Specializing in All of You: Children, Adults, Seniors & Women's Health |