A Better Measure of Medical Error

In what is believed to be the first rigorous national estimate of permanent disability and death from medical diagnostic error, a team from Johns Hopkins and Harvard’s Risk Management Foundation found that across all clinical settings — including hospital and clinic-based care — an estimated 795,000 Americans die or are permanently disabled by diagnostic error each year, confirming the pressing nature of the public health problem.

“Prior work has generally focused on errors occurring in a specific clinical setting, such as primary care, the emergency department or hospital-based care,” says David Newman-Toker, lead investigator and director of the Johns Hopkins Armstrong Institute Center for Diagnostic Excellence.

“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 says. The results of the new analysis of national data were published in BMJ Quality & Safety.

Vascular events, infections and cancers, dubbed the Big Three, account for 75% of the serious harms, the study found. The researchers suggest that diseases accounting for the greatest number of serious misdiagnosis-related harms and with high diagnostic error rates should become top-priority targets for developing, implementing and scaling systematic solutions.  

“A disease-focused approach to diagnostic error prevention and mitigation has the potential to significantly reduce these harms,” Newman-Toker says. “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.” 

Newman-Toker adds that disease-based solutions have already been developed and deployed at Johns Hopkins to address missed stroke, the top identified cause of serious harms.

These solutions include virtual patient simulators to improve frontline clinician skills in stroke diagnosis, portable eye movement recordings via video goggles and mobile phones to enable specialists to remotely assist frontline clinicians in diagnosing stroke, computer-based algorithms to automate aspects of the diagnostic process to facilitate scaling, and diagnostic excellence dashboards to measure performance and provide feedback on quality improvement. 

“Funding for these efforts remains a barrier,” Newman-Toker says. “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.”