1 in 3 misdiagnoses results in serious injury or death: study

One-third of malpractice cases that result in death or permanent disability come from a misdiagnosis or a delayed diagnosis.

According to a study conducted by the Johns Hopkins University School of Medicine and appearing in Diagnosis, data confirm that an inaccurate diagnosis is the No. 1 cause of serious medical errors.

An estimated 40,000 to 80,000 deaths occur each year in U.S. hospitals related to misdiagnosis, and an estimated 12 million Americans suffer a diagnostic error each year in a primary care setting—33% of which result in serious or permanent damage or death.

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In total, these severe cases cost the system $1.8 billion in malpractice payouts over the span of 10 years.

The research, funded by the Society to Improve Diagnosis in Medicine, analyzed more than 55,000 malpractice claims from the Comparative Benchmarking System database. Of the diagnostic errors causing the most harm, 74.1% were attributed to just three categories—referred to in the paper as “The Big Three”: cancer (37.8%), vascular events (22.8%) and infection (13.5%).

Within The Big Three, the top five diseases under each category (15 total) accounted for 47.1% of all high-severity misdiagnosis-related cases and 63.5% of all Big Three high-severity cases. More specifically, the top misdiagnosed vascular disease was stroke, the top misdiagnosed infection was sepsis and the top misdiagnosed cancer was lung cancer.

A majority of the diagnostic errors, 71.2%, occurred in ambulatory settings, specifically in outpatient clinics or emergency departments (EDs). The number of high-severity cases from EDs and inpatient settings were higher for vascular events and infections, while those in non-ED care setting were higher for cancers—with the exception of pediatric care where infections dominated.

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“If we’re going to reduce serious harms from medical errors, major strides must be made to improve diagnostic accuracy and timeliness. This study shows us where to focus to start making a difference for patients. It tells us that tackling diagnosis in these three specific disease areas could have a major impact on reducing misdiagnosis-related harms,” David Newman-Toker, M.D., professor of neurology at the Johns Hopkins University School of Medicine, said in a statement.

The authors of the study did stress that improving diagnosis is not just a burden for physicians, but system wide. They also noted that quality improvement efforts need to focus on interventions in the specific practice settings where the harm occurs, such as “stroke in the emergency department, sepsis in the hospital and lung cancer in primary care.”
When it comes to payouts for misdiagnosis claims, payments were greatest for infection, followed by vascular events and then cancers.

Over half of the cases involved general care physicians. The other primary responsible services were divided almost evenly among medical specialties, general surgery and diagnostic service providers.

“This study confirms that diagnostic errors remain the most common, most catastrophic and most costly of serious medical errors in closed malpractice claims,” the paper stated.  

More importantly, the causes of these wrong diagnosis were nearly uniformly associated with clinical judgement failures—more than 85% of cases.

There was a noted difference in that cancer cases had higher rates of failing to “close the loop,” as diagnostics with cancer usually happen over a longer period of time and over a series of outpatient visits.

Still, these diagnostic mistakes are dwarfed by clinical judgement, which accounted for more than 80% of cancer cases.