Understanding Evidence Based Medicine

Understanding Evidence Based Medicine
Evidence-based medicine allows doctors and scientists to help understand complicated research and offer patients the best solution to solve their problems, help maintain their health and live a longer life free of disease. Dr Sackett formed a good basic definition of evidence-based medicine(1): "Evidence-based medicine is the conscientious explicit and judicious use of current best evidence in making decisions about the care of individual patients". How does the average person understand and trust these complex ideas? Reading, learning and trust are the basis of advancing our understanding of this complex process.

There are two main kinds of studies: observational and experimental. In observational studies you “observe” peoples actions and record the outcomes. The patient decides whether to do or not do something. This could be taking or not taking the flu shot. You then might measure how many people got the flu or died if they did or did not get the flu shot. From a scientific standpoint a “better” study is an experimental study that takes 30,000 similar people and randomly give them a real flu shot or a placebo (sterile saline) shot without the doctor or patient knowing if they are getting the real or placebo shot (“double blind study”). You then follow them for eight months and measure how many in each group get the flu or die from the flu.

Ethically we could not do an experimental flu study today because we know from multiple studies that the flu vaccine saves lives and prevents the flu. Knowing that you could cause a preventable death or severe disease by giving a patient the placebo would make it ethically unacceptable. We did do experimental studies to test if giving high dose (four times the amount) flu shots to seniors over 65 years old was better than the old standard dose. Fewer cases of the flu and fewer deaths from the flu was the result of using the high dose. This was ethically possible because we were unsure if the higher dose was better or would make no difference. We learned that seniors have weaker immune responses and the higher dose resulted in lower flu rates and lower flu deaths. This also means we can no longer do experimental studies using the old lower dose when we know that allowing them to get the higher dose saves more lives. Many patients falsely believe that the flu shot can give them the flu and therefore refuse to get the flu shot. The flu shot is a killed virus and it is impossible for it to give anyone the flu. In 2014 the CDC(3,4) estimated that 25,000 US deaths form the flu could have been prevented if everyone had received the flu shot.

It is still ethically acceptable to do observational studies on patients that refuse the flu and other vaccines because they have the right to make bad decisions. Observational studies are cheaper and not as scientifically valid as experimental studies. Typically, we start out with multiple observational studies and if most show a benefit of a medication (including vaccines) then it is reasonable to do an experimental study to confirm the results. Once confirmed, it is not ethical to withhold life saving treatment to do additional studies. In 1952 the CDC estimated there were 58,000 US cases of polio and 3,000 deaths. Since 2000 we have had no “wild” cases of polio and only cases brought in from other countries. India and Pakistan are the only remaining countries in the world with polio. It will soon be eliminated just like smallpox. Before the MMR (measles, mumps and Rubella) vaccine there about 700,000 cases of US measles in 1952 and over 600 deaths. In 2016 there were only 85 cases (unvaccinated children) and no deaths. Please check out “What if we stop vaccines”(3,4).

EBM has shown that vaccines are safer than not getting vaccines. People opposed to vaccines in earlier times left their children at risk to disease like polio and smallpox. you have the freedom to choose to get or not get recommended vaccines. Unfortunately some parents put their children at risk of disease or death that would have been preventable had they been vaccinated. The children pay the price of the misinformed parents. Look at all sides of the story before making the decision. The only reason children are no longer dying of polio, smallpox, and many other diseases is because our parents and grandparents made the right choices and got us vaccinated.
Further reading(5) for EBM.

References

1. [1] David Sackett, William Rosenberg, Muir Gray, Brian Haynes & Scott Richardson. Evidence based medicine: what it is and what it isn’t [internet]. BMJ; 13 January 1996 [cited 23 May 2013]. Available from: http://www.bmj.com/content/312/7023/71
2. http://blogs.trusttheevidence.net/ami-banerjee/understanding-evidence-based-medicine-in-4-days-lesson-1-clinical-significance-is-all-a
3. https://www.cdc.gov/vaccines/vac-gen/whatifstop.htm
4. Reed C, Chaves SS, Daily Kirley P, Emerson R, Aragon D, Hancock EB, et al. (2015) Estimating Influenza Disease Burden from Population-Based Surveillance Data in the United States. PLoS ONE 10(3): e0118369. https://doi.org/10.1371/journal.pone.0118369
5. JAMA.2000;284:1290-1296