One in 10 Patients with a ‘Big Three’ Disease Misdiagnosed

Study: Patients with major vascular events, infections, or cancers most likely to receive inaccurate or delayed diagnoses resulting in serious harm

Evanston, IL - (May 14, 2020) One in 10 people (9.6%) with symptoms caused by a major vascular event, infection, or cancer will be misdiagnosed, according to a study from researchers at the Johns Hopkins University School of Medicine and CRICO Strategies.

Published today in the academic peer-reviewed journal Diagnosis, the study provides estimates of diagnostic error and serious misdiagnosis-related harm rates for each of the five most frequently misdiagnosed major vascular events, infections, and cancers, together referred to by authors as the “Big Three.”

Of people inaccurately diagnosed with any of the top 15 “Big Three” conditions, about half (53.9%) suffer a permanent disability or death because of the error and represent roughly half of all the diagnostic error-related serious harms across all conditions.

The study was funded by the Society to Improve Diagnosis in Medicine (SIDM), through a grant from the Gordon and Betty Moore Foundation.

“Delayed and inaccurate diagnoses are a serious threat to patient safety, especially for people with cancers, infections, or major vascular events, such as stroke or heart attack,” said lead author David Newman-Toker, MD, PhD, director of the Armstrong Institute Center for Diagnostic Excellence at Johns Hopkins and president of the board of SIDM. “Misdiagnoses can have catastrophic effects, leaving patients and their families picking up the pieces after a death or permanent disability.”

Not all diseases are equally likely to be misdiagnosed. For infections and major vascular events, the authors found that the more uncommon diseases are most likely to be missed; by contrast, for cancers, it appears to be those with the least successful diagnostic screening programs. Among the 15 diseases analyzed, spinal abscesses (an infection that can compress the spinal cord and cause paraplegia) was the disease most often missed (62.1%). More than one in four aortic aneurysms and dissections have a critical delay in diagnosis (27.9%). More than one in five (22.5%) lung cancer diagnoses are also meaningfully delayed.

The authors say the study should be used to target efforts to improve diagnosis among these conditions. They note that misdiagnoses of major vascular events, infections, and cancers do not appear to have declined over the last several decades due, in large part, to a lack of research funding focused on improving diagnosis for most of these conditions. For some individual diseases, such as stroke and aortic aneurysms, they may even be rising.

“The possibility that misdiagnosis might actually be on the rise for some conditions is something we should all be worried about—the last thing we need is for a problem already acknowledged by the National Academy of Medicine to be a ‘blind spot’ for modern medicine and a ‘public health imperative’ to be getting worse,” said Newman-Toker, who also is a professor of neurology at the Johns Hopkins University School of Medicine.

Bipartisan legislation to begin to tackle this problem was introduced in the U.S. House of Representatives in November 2019. The Improving Diagnosis in Medicine Act would fund 4-8 new Research Centers of Diagnostic Excellence at U.S. academic medical organizations and require federal healthcare agencies to clear pathways in their own funding portfolios for more diagnosis-related research.

“The legislation is a very important indicator that policymakers are beginning to recognize the outsized public health burden of diagnostic error that has, until very recently, flown under the quality and safety radar,” said Paul Epner, CEO and co-founder of the Society to Improve Diagnosis in Medicine (SIDM). “It is an important first step as we begin to tackle a problem that is costing hundreds of thousands of lives and likely over 100 billion annually in wasted healthcare dollars.”

The new study’s findings build on previous research from the CRICO Strategies Comparative Benchmarking System (CBS) database, showing that one in three malpractice cases with serious patient harms is due to a misdiagnosis. “The unique lens of malpractice data allows us to identify specific contributing factors driving these high-severity cases,” said Dana Siegal, RN, CPHRM, CPPS, director of patient safety at CRICO Strategies and a co-author of the study. “With this insight, healthcare leaders and clinicians can focus their resources and interventions to target the specific process and system vulnerabilities contributing to these diagnostic errors.”

One effort to address the multi-faceted problem of diagnostic error is the Coalition to Improve Diagnosis, comprising more than 50 national organizations committed to initiatives to improve diagnostic quality and safety. This group, convened by SIDM, represents health systems, patients and families, clinicians, risk managers, testing professionals, and others. Its collective actions are contributing to raising the profile of diagnostic errors, promoting policy action, and mobilizing clinical solutions.

“The process of making a diagnosis involves a team of healthcare professionals and the patients they serve, so you need all stakeholders collaborating to move the needle on quality and safety,” said Epner. “We’re bringing together organizations from every corner of healthcare to leverage their insights and experiences to implement real solutions that result in tangible improvements.”

SIDM is the only organization focused solely on the problem of diagnostic error and improving the accuracy and timeliness of diagnosis.


About the Society to Improve Diagnosis in Medicine
The Society to Improve Diagnosis in Medicine catalyzes and leads change to improve diagnosis and eliminate harm from diagnostic error. We work in partnership with patients, their families, the healthcare community and every interested stakeholder. SIDM is the only organization focused solely on the problem of diagnostic error and improving the accuracy and timeliness of diagnosis. In 2015, SIDM established the Coalition to Improve Diagnosis to increase awareness and actions that improve diagnosis. Members of the Coalition represent hundreds of thousands of healthcare providers and patients—and the leading health organizations and government agencies involved in patient care. Together, we work to find solutions that enhance diagnostic safety and quality, reduce harm, and ultimately, ensure better health outcomes for patients. Visit to learn more.

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Learn more about the rate and impact of misdiagnoses and related serious harms for top five diseases in each category.