Misdiagnosis Tied to Serious Harm of 795K Americans Annually, Study Finds

About 371,000 Americans die annually after a false negative diagnosis for a serious illness, according to researchers.

False negative diagnoses are likely the largest source of death linked to medical errors in the United States, a new research article found.

The U.S. National Academy of Medicine says improving diagnosis is a "moral, professional, and public health imperative." In a 2015 report, the National Academy of Medicine estimated that most Americans have at least one diagnostic error in their lifetime that can lead to "devastating consequences."

The new research article, which was published by BMJ Quality & Safety, extrapolates total false negative diagnoses that result in death or permanent disability from "The Big Three" disease categories for misdiagnosis with serious harm: vascular events, infections, and cancers. The researchers focused on 15 diseases in The Big Three categories: stroke, venous thromboembolism, arterial thromboembolism, aortic aneurysm/dissection, myocardial infarction, sepsis, pneumonia, meningitis/encephalitis, spinal abscess, endocarditis, lung cancer, breast cancer, colorectal cancer, melanoma, and prostate cancer.

The study features several key findings:

• About 795,000 Americans suffer death or permanent disability after a false negative diagnosis for a serious illness at an ambulatory clinic, emergency department, or inpatient setting, with 371,000 deaths and 424,000 permanent disabilities
   
• The 15 serious diseases that were the focal point of the study account for 50.7% of deaths and permanent disabilities linked to false negative diagnoses
   
• Five of the 15 diseases that were the focal point of the study account for 38.7% of deaths and permanent disabilities linked to false negative diagnoses: stroke, sepsis, pneumonia, venous thromboembolism, and lung cancer
   
• The overall average diagnosis error rate was estimated at 11.1%
   
• The disease with the highest rate of death and permanent disability linked to false negative diagnosis was stroke, which was missed in 17.5% of cases

Interpreting the data

The study is the first rigorous national estimate of death and permanent disability linked to diagnostic errors, David Newman-Toker, MD, PhD, lead investigator of the research and director of the Johns Hopkins Armstrong Institute Center for Diagnostic Excellence said in a prepared statement.

"Prior work has generally focused on errors occurring in a specific clinical setting, such as primary care, the emergency department, or hospital-based care. These studies could not address the total serious harms across multiple care settings, the previous estimates of which varied widely from 40,000 to 4 million per year. The methods used in our study are notable because they leverage disease-specific error and harm rates to estimate an overall total," he said.

Efforts to improve diagnosis should focus on diseases accounting for the greatest number of serious misdiagnosis-related harms and with high diagnostic error rates, Newman-Toker said. "A disease-focused approach to diagnostic error prevention and mitigation has the potential to significantly reduce these harms. Reducing diagnostic errors by 50% for stroke, sepsis, pneumonia, pulmonary embolism, and lung cancer could cut permanent disabilities and deaths by 150,000 per year."

There is an urgent need for more research designed to examine diagnostic errors and point to possible solutions, he said. "Funding for these efforts remains a barrier. Diagnostic errors are, by a wide margin, the most under resourced public health crisis we face, yet research funding only recently reached the $20 million per year mark. If we are to achieve diagnostic excellence and the goal of zero preventable harm from diagnostic error, we must continue to invest in efforts to achieve success."

The researchers found conservative estimates of serious harm from diagnostic errors compelling, the study's co-authors wrote. "Even with the most conservative assumptions about disease incidence or disease-specific harms, we estimated the number affected [patients] to be over 500,000. The number of affected patients is large, and this makes diagnostic error a pressing public health concern."

Diagnostic errors could be the most deadly medical errors in U.S. healthcare, the co-authors wrote. "Our results suggest that diagnostic error is probably the single largest source of deaths across all care settings (~371,000) linked to medical error."

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