25 Times Medical Consensus Had To Be Rethought

These examples are a reminder of the need for ongoing research, humility, and the willingness to challenge established beliefs for the sake of patient care.

There’s been much debate lately about the value of medical consensus.

“What matters is consensus!” astrophysicist Neil deGrasse Tyson excitedly told Del Bigtree, on a recent episode of The Highwire. He seemed to be arguing that medical or scientific “consensus” is more important than the knowledge and experience of individual scientists.

Medical certification and licensing boards also claim that individual healthcare providers who share information that is contrary to “consensus-driven scientific evidence” are misinformation spreaders who cause so much potential harm that their certifications or licenses should be revoked.

While some might argue in favor of the merits of consensus in providing timely guidance, it is important to correct for the many potential biases, beliefs, preferences, and conflicts of interest that could lead to subjective consensus decisions, and to ensure that consensus-based recommendations reflect the views of a heterogenous and diverse group of experts.

How can it be a consensus when all sides of an issue have not been considered and differing views are being censored? What about all the out-of-the-box thinkers in history who have challenged conventional thinking and moved the needle forward for all humankind?

Consensus is, in fact, a perfect cover for conflicts of interest like ties to pharmaceutical companies, medical device manufacturers, or other commercial entities, which compromise the integrity and impartiality of the consensus process. Or, some experts may be more inclined to favor consensus recommendations aligned with the interests of their research funding sources. Others may have intellectual biases based on long-standing beliefs or theories they are hesitant to challenge.

And what about all the times in medical history when consensus beliefs were proven wrong, and patients were harmed in the process because the establishment clung to a flawed premise?

Once a consensus is reached, there is often resistance to updating recommendations based on new and emerging evidence, which leads to guidelines becoming quickly outdated and not reflecting the latest advances in science. Studies have shown that even after claims have been disproven in the medical literature, they often persist for years and even decades before they retreat from use. 

Dr. David Sackett, considered one of the ‘fathers’ of evidence-based medicine, once had this advice for medical students:

"Half of what you’ll learn in medical school will be shown to be either dead wrong or out of date within five years of your graduation; the trouble is that nobody can tell you which half – so the most important thing to learn is how to learn on your own."

[Incidentally, Sackett also cautioned students to “remember that your teachers are as full of bullshit as your parents,” but that’s a topic for another article!]

Here are 25 times the medical consensus had to be revisited. This list is in no particular order and is by no means exhaustive. We share these examples simply as a reminder of the need for ongoing research, humility, and the willingness to challenge established beliefs in the pursuit of patient-centered healthcare.

1. Thalidomide and Birth Defects (1950s-1960s)

In the late 1950s and early 1960s, thalidomide, a sedative, and anti-nausea medication, was widely prescribed to pregnant women to alleviate morning sickness. Regrettably, it was believed to be safe for use during pregnancy, even though some animal studies indicated potential risks. Tragically, thousands of babies were born with severe limb deformities, known as phocomelia, because their mothers took thalidomide during pregnancy. This devastating outcome exposed the flaws in the medical consensus of the time and led to the establishment of stricter drug safety regulations.

2. Hormone Replacement Therapy (HRT) and Cardiovascular Disease (1990s-2000s)

HRT was commonly prescribed to postmenopausal women during the 1990s and early 2000s to alleviate menopausal symptoms and prevent cardiovascular disease. However, a large-scale study called the Women's Health Initiative (WHI) conducted in 2002 found that long-term use of HRT was associated with an increased risk of heart disease, stroke, blood clots, and breast cancer. This overturned the prevailing belief that HRT was a protective measure against heart disease and underscored the need for rigorous testing of treatments before widespread adoption. The medical consensus on HRT for menopausal symptoms underwent a significant revision in the early 2000s, shifting towards limited and individualized use of HRT for symptom management and only for the shortest duration necessary.

3. Stomach Ulcers and Stress (20th Century)

For much of the 20th century, the medical consensus held that stomach ulcers were primarily caused by stress, spicy foods, and excessive acid secretion. However, in the 1980s, Australian scientists Barry J. Marshall and Robin Warren discovered that the bacterium Helicobacter pylori was responsible for most stomach ulcers. Despite facing skepticism from the medical community initially, their findings eventually led to a paradigm shift in ulcer treatment, with antibiotics becoming a crucial component of therapy.

4. Dietary Fat and Heart Disease (1970s-1990s)

For several decades, there was a widespread belief among health professionals that dietary fat, particularly saturated fat, was the primary cause of heart disease. Consequently, low-fat diets gained popularity as a means to reduce cardiovascular risk. However, later research, such as the large-scale PURE study published in 2017, questioned this consensus, suggesting that excessive carbohydrate consumption might play a more significant role in heart disease risk than previously thought. This revelation challenged long-standing dietary guidelines and led to a reevaluation of the relationship between fats, carbohydrates, and heart health.

5. Smoking and Health Risks (20th Century)

For much of the 20th century, the tobacco industry worked tirelessly to cast doubt on the harmful effects of smoking, while medical professionals were slow to recognize the dangers. Smoking was initially endorsed and even advertised as a harmless or health-enhancing habit. It wasn't until landmark studies, such as the 1964 Surgeon General's Report, that smoking was unequivocally linked to lung cancer, heart disease, and a myriad of other health issues. The battle against tobacco use highlighted the dangers of delaying action due to industry influence and the importance of evidence-based decision-making in public health.

6. Cholesterol and Heart Disease Risk (20th Century - 21st Century)

For many years, the medical consensus held that high cholesterol levels, specifically LDL cholesterol, were a primary risk factor for heart disease. However, more recent research has revealed that it is not just the total cholesterol levels that matter, but also the ratio of LDL to HDL cholesterol, as well as other factors like inflammation and triglyceride levels. This led to a shift in focus from solely targeting cholesterol levels to a more comprehensive approach to assess cardiovascular risk.

7. Bloodletting (Ancient Times - 19th Century)

Bloodletting, the practice of deliberately withdrawing blood from a patient, was a widely accepted medical treatment for various illnesses in ancient times and throughout the Middle Ages. It was believed to restore the balance of bodily humors. However, with advancements in medical knowledge, the practice was eventually recognized as ineffective and potentially harmful, leading to its abandonment.

8. Prostate-Specific Antigen (PSA) Testing for Prostate Cancer (1990s - Present)

PSA testing was initially hailed as a revolutionary tool for the early detection of prostate cancer. However, over time, it became evident that PSA testing led to overdiagnosis and overtreatment of low-risk prostate cancers. As a result, the medical consensus has evolved to be more selective in recommending PSA testing, taking into account individual patient risk factors.

9. Opioid Prescribing for Chronic Pain (Late 20th Century - 21st Century)

There was a time when opioids were commonly prescribed for various types of chronic pain conditions. However, the opioid epidemic that followed highlighted the dangers of overprescribing and the potential for addiction and overdose. The medical consensus has since shifted towards more judicious and cautious use of opioids for chronic pain management, emphasizing alternative treatments and multidisciplinary approaches.

10. Dietary Recommendations for Saturated Fat and Sugar (20th Century - 21st Century)

As our understanding of nutrition has evolved, so have dietary recommendations. The once-held belief that saturated fat was the primary cause of heart disease has been challenged, and more emphasis is now placed on the type of fat and overall diet quality. Similarly, growing evidence on the negative health effects of excessive sugar consumption has led to updated guidelines and warnings about sugar intake.

11. High-Dose Chemotherapy and Bone Marrow Transplant for Breast Cancer (1990s)

In the 1990s, high-dose chemotherapy followed by autologous bone marrow transplant was considered a promising treatment for advanced breast cancer. However, subsequent research did not demonstrate a significant improvement in survival rates compared to standard chemotherapy. The medical consensus shifted away from high-dose chemotherapy as a routine treatment for breast cancer due to its increased toxicity and lack of survival benefit.

12. Bed Rest for Low Back Pain (2010s)

For many years, the medical consensus advised bed rest as a common treatment for low back pain. However, research in the 2010s revealed that prolonged bed rest could lead to muscle deconditioning and delay recovery. The revised consensus now recommends staying active and engaging in gentle exercises for most cases of acute low back pain.

13. Screening Mammography Guidelines (2000s-2010s)

The recommended age and frequency for mammography screening have been subject to revision over the years. Earlier consensus guidelines suggested annual mammograms starting at age 40 for all women. However, more recent research and debates within the medical community have led to variations in recommendations, such as starting mammograms at age 45 or 50 and screening every one to two years. The revision reflects a more nuanced approach that considers individual risk factors and preferences.

14. Antidepressant Use in Children and Adolescents (2000s)

Selective Serotonin Reuptake Inhibitors (SSRIs) were commonly prescribed to children and adolescents for depression and other mental health conditions. However, in the early 2000s, concerns about an increased risk of suicidal thoughts and behaviors emerged in this age group. The medical consensus shifted, and regulatory authorities issued warnings about the use of SSRIs in pediatric patients, leading to more cautious prescribing practices that emphasized close monitoring and a risk-benefit assessment.

15. Stenting for Stable Coronary Artery Disease (2010s)

For many years, coronary artery stenting was considered a standard treatment for stable coronary artery disease. However, research studies, such as the ORBITA trial published in 2017, suggested that stenting did not provide significant additional benefit over optimal medical therapy alone in certain cases. The findings prompted a reevaluation of stent use, with an increased emphasis on lifestyle changes and medical management for some patients with stable coronary artery disease.

16. Blood Pressure Targets for Hypertension (2010s)

For many years, the medical consensus recommended aggressive blood pressure targets for hypertension, aiming for levels below 130/80 mmHg for most patients. However, in 2017, the Systolic Blood Pressure Intervention Trial (SPRINT) found that a more conservative target of 120/80 mmHg led to better outcomes in high-risk patients. This resulted in a revision of guidelines, with a more individualized approach to blood pressure management, considering factors like age, comorbidities, and overall health status.

17. Use of Aspirin for Primary Prevention of Cardiovascular Disease (2010s)

Aspirin was once widely recommended for the primary prevention of cardiovascular disease in individuals without a history of heart attacks or strokes. However, emerging evidence showed that the benefits of aspirin in primary prevention might be outweighed by the risk of bleeding. The revised consensus shifted towards a more selective approach, considering individual risk factors before recommending aspirin for primary prevention.

18. Oxygen Therapy for Acute Myocardial Infarction (AMI) (2010s)

For decades, the medical consensus was to provide supplemental oxygen to all patients with acute myocardial infarction (heart attack). However, studies, such as the AVOID trial published in 2016, suggested that routine oxygen therapy might not improve outcomes and could even be associated with adverse effects. As a result, guidelines were updated to recommend oxygen therapy only for patients with low oxygen saturation levels.

19. Antibiotics for Acute Otitis Media (AOM) in Children (2010s)

Previously, antibiotics were routinely prescribed for children with acute otitis media (middle ear infection). However, growing concerns about antibiotic resistance and limited benefits in certain cases led to a revised consensus. Current guidelines recommend a more watchful waiting approach for children with uncomplicated AOM, reserving antibiotics for those with severe symptoms or high risk of complications.

20. Beta-Blockers for Heart Failure with Preserved Ejection Fraction (HFpEF) (2010s)

Beta-blockers were long considered a cornerstone of treatment for heart failure with reduced ejection fraction (HFrEF). However, their effectiveness in heart failure with preserved ejection fraction (HFpEF) was uncertain. Recent studies, such as the TOPCAT trial published in 2014, showed no significant benefit of beta-blockers in HFpEF patients, leading to a revised consensus that focuses on other management strategies for this specific heart failure subtype.

21. High-Intensity Statin Therapy for Primary Prevention (2010s)

The medical consensus once recommended high-intensity statin therapy for primary prevention in individuals with elevated cardiovascular risk, irrespective of cholesterol levels. However, updated guidelines, such as those from the American College of Cardiology/American Heart Association (ACC/AHA) in 2018, shifted towards a risk-based approach, suggesting statin therapy based on an individual's overall cardiovascular risk profile.

22. Extended Dual Antiplatelet Therapy (DAPT) after Coronary Stent Placement (2010s)

For patients who received coronary stents, medical consensus initially recommended extended dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) beyond 12 months to prevent stent thrombosis. However, recent studies like the DAPT trial indicated that the benefits of prolonged DAPT may be offset by an increased risk of bleeding, leading to more individualized recommendations for DAPT duration based on the patient's bleeding and ischemic risk.

23. Use of Hypothermia for Cardiac Arrest (2010s)

Therapeutic hypothermia was widely recommended for comatose survivors of out-of-hospital cardiac arrest to improve neurological outcomes. However, studies like the TTM trial published in 2013 showed that targeted temperature management at either 33°C or 36°C had similar outcomes. As a result, the medical consensus shifted towards a range of target temperatures, allowing for more personalized approaches to post-cardiac arrest care.

24. Early Introduction of Allergenic Foods to Prevent Food Allergies (2010s)

The medical consensus previously recommended delaying the introduction of allergenic foods (e.g., peanuts, eggs) to infants to prevent food allergies. However, the LEAP and EAT studies demonstrated that early introduction of allergenic foods, in some cases as early as 4-6 months, could reduce the risk of developing allergies. This led to revised guidelines recommending the early introduction of allergenic foods in infants at low risk of allergies.

25. Prophylactic Antibiotics for Infective Endocarditis (2000s)

For many years, the medical consensus recommended prophylactic antibiotics before dental procedures in individuals with certain heart conditions to prevent infective endocarditis. However, evidence showed that the risk of adverse reactions from antibiotics outweighed the benefits of preventing infective endocarditis in low-risk patients. As a result, guidelines were revised, and the use of prophylactic antibiotics was restricted to specific high-risk patients only.