Medical school taught me many lessons that ring true to this day.  However, there are some lessons from medical school that I have unlearned since graduating medical school because I have found these are largely not true.

These untruths I have unlearned are:

1.     Standard of care practice is always medical truth.

2.     Once a disease is established, it is established.

3.     Medical science reveals absolute truth.

4.     We have most diseases figured out.

Let me discuss these one at a time.

1.     Untruth: Standard of care practice is always medical truth.

Medical school often teaches standard of care practice as absolute truths.  For example, when discussing treatment of a given medical diagnosis such as hypertension or high cholesterol, specific medications are generally framed as the best first-line treatments. A new medical student memorizes such facts, restates this information on clinical services and medical licensing exams, and graduates feeling like the truth regarding best standard of care practices has been taught and received.

However, I learned within my first year of graduating medical school that several medical truths regarding standard of care practice I perceived as absolute during my medial career were not. One reason why is I that I did not appreciate how clinical research can in some instances rapidly overturn widely accepted medical truths. I specifically remember during my intern year reviewing results of a just-published groundbreaking study informing that a medication commonly prescribed as first-line treatment for hypertension had very limited effect in many hypertensive patients.  This was a medication taught in pharmacology and reinforced in the clinic as the best first-line treatment for most patients newly diagnosed with hypertension.

More than a decade has now passed since I graduated medical school. During this time, I have seen several standard of care medical practices become completely or partially overturned. This has caused me to appreciate that many standard of care practices are not absolute in medicine.  In certain cases, even our most widely appreciated truths can be found to be incorrect.  More commonly, new advances will be made that make prior truths fully or partially obsolete.

Truth in medicine—as in all of science—evolves.

How often does this occur?  On my first day of medical school, my dean of the school of medicine taught an important lesson about truth in medicine. In front of a room full of eager future doctors he proclaimed that 90% of what we will be taught in medical school is true and 10% is not. The problem is that the faculty did not currently know what 10% is untrue. 

From my own experience this is approximately correct.  My best guess is that 5% of what we currently consider truth in medicine is not, and another 5% of what we think of as true is only partially true. In other words, 5% of medical knowledge may be false and another 5% is only partial truth.  In terms of standard of care medical practice, what is considered standard of care is a best-informed guess based on incomplete data. This is something I did not sufficiently appreciate upon graduation of medical school.

Progress demands adaptation. Pending a perfect knowledge of the body and mind some proportion of commonly accepted medical knowledge will be untrue. Therefore, question absolutes in medicine.  Keep an open mind and a broad perspective. Do not assume that everything you were taught in medical school must be true.

Truth: Standard of care medical practice is a best-informed guess in many instances.

2.     Untruth: Once a disease is established, it is established. 

Medical diagnoses are all about patterns and divisions and groupings.  Medical knowledge is organized into an intricate branching tree of knowledge, in which branch points diverge based on various clinical symptoms and conclude terminally as a disease or diagnosis.  Like an actual growing tree, this branching of medical knowledge and disease states is dynamic. As the tree enlarges, more diagnoses become defined and new disease are added to the tree.  What was previously a terminal branching point will someday get sub-divided again, and perhaps again. In other cases, problematic branches of medical knowledge are pruned, and diseases are re-classified according to new and more accurate knowledge.

I have seen this happen since medical school graduation. For example, as a medical student, I diligently memorized the 4th edition of the WHO classification of CNS tumors. I recently read the 5th edition of the WHO classification of CNS tumors.  I was shocked by how much this disease classification changed, especially given that CNS tumors are generally very similar today in comparison to a decade ago. The lesson I learned is that new knowledge can cause us to dramatically re-write disease classifications, even if the disease itself does not change.

Diseases are therefore best viewed as temporary placeholders representing groupings of dynamic knowledge.  

By the way, the same principle holds true for medical therapies.  What is the best therapy today, particularly for pharmacologic interventions, is merely a placeholder that will very likely be replaced in the future.

Truth: View diseases as temporary placeholders.

3.     Untruth: Medical science reveals absolute truth.

As a medical student, I was taught that medical science reveals the truth regarding best practices in medicine, and that randomized controlled trials reveal absolute truth in medicine. I now understand that truths borne from medical science, even from randomized controlled trials, are expressed in terms of likelihood rather than absolutes. In medicine, we essentially never conduct any trial that reveals confirmed truth. The best we can do, even with our most intricate and well-designed studies, is arrive at results that are very likely to be the truth, though we never know for sure whether the results of a trial tells are absolute truth.

Another pillar of scientific practice is that studies are repeated to prove results more definitively.  As a medical student, I was taught this principle, and I naively believed that this frequently occurred in medicine. I now understand that repeating studies to confirm results of prior trials rarely occurs in medicine. Reasons why include the expense and complexity of medical science, a relatively small cadre of investigators and teams available to retest studies, and the sheer number of questions that need answering in medicine leading many investigators to study a new question rather than repeat the work of prior investigators. This lack of repeating most medical studies limits our ability to approximate absolute truth in medical knowledge.

The pace of clinical trials is frequently too slow relative to human lifespans, and as a result the knowledge we obtain from medical studies is often short sighted.  For example, medical knowledge could greatly benefit from studies that span many decades of life, yet those that influence and support medical science generally are not that patient.  As a result, clinical trials generally only observe for outcomes over the course of a few years.  Additionally, the sheer expense of testing expensive drugs and therapeutics, and the difficulty enrolling participants onto trials, means that many trials that are performed are statistically underpowered, further limiting our ability to be confident in results. As a result, even our best peer-reviewed publications of our most rigorous clinical trials often include disclaimers like “further studies are needed to confirm these findings”. In most cases, further studies are not forthcoming.

Many important questions in medicine have little empiric truth from published literature to guide best practices.  We should be grateful, therefore, for all data that we do have. In scenarios where data to inform clinical decision making is weak, medical practice will generally be guided by expert opinion. This is hopefully a reasonable surrogate for truth. Unfortunately, I have already seen in my career that the opinions of experts is not always correct and is subject to groupthink and other group-decision biases. Although expert consensus is a necessity in medicine this does not equal empirical data from medical science, and may not reflect the truth.

Truth: Medical science reveals truths as likelihoods, but not absolutes, is rarely definitive, and always has the potential for error.

4.     Untruth: We have most diseases figured out.

I graduated medical school believing that we have most disease figured out.  This resulted from years of lectures running through disease classifications and appropriate treatments, and rounding on wards where medical diagnoses were always paired with corresponding treatments.  As a medical student, I daily witnessed the matching of symptoms with diagnoses, and diagnoses with treatments.  This causes one to graduate feeling like we have this figured out. 

Unfortunately, the length of time on most medical services as a medical student, which ranged from 4 to 8 weeks, was not sufficient to witness whether our interventions achieved the desired outcomes, except for acute emergencies.  

I have learned since medical school that there are too many scenarios wherein we do not have everything figured out. We typically do best with acute emergencies such as trauma, and often struggle most with chronic disease states to include things as classic as hypertension and diabetes.

Despite all the vast medical knowledge we have amassed as society, there are many medical mysteries that remain mysterious, many patient symptoms that are poorly diagnosed, and too little treatments available for important diseases that include many types of cancer and dementia.

Don’t get me wrong: we have made remarkable progress with many diseases.  Medicine reduces morbidity and mortality from many diseases, and offers hope for many situations that previously were hopeless. However, our work to prevent and cure even some of our most classic diseases is not complete. We are still figuring this out.

Truth: For many diseases, we are still figuring things out.

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