Diagnostic errors are your biggest medmal risk

Twenty-five years of U.S. medical malpractice claim payouts show that diagnostic errors accounted for the largest fraction of claims, the most severe patient harm, and the highest total of penalty payouts, according to recent research from The Johns Hopkins University in Baltimore, MD.

Diagnosis-related payments amounted to $38.8 billion between 1986 and 2010, says David E. Newman-Toker, MD, PhD, an associate professor of neurology at the Johns Hopkins University School of Medicine and leader of the study published online in BMJ Quality and Safety. “This is more evidence that diagnostic errors could easily be the biggest patient safety and medical malpractice problem in the United States,” Newman-Toker says. “There’s a lot more harm associated with diagnostic errors than we imagined.”

While the new study looked only at a subset of claims — those that rose to the level of a malpractice payout — Newman-Toker says other research indicates that the number of patients suffering misdiagnosis-related, potentially preventable, significant permanent injury or death annually in the United States ranges from 80,000 to 160,000.

“Overall, diagnostic errors have been underappreciated and under-recognized because they’re difficult to measure and keep track of, owing to the frequent gap between the time the error occurs and when it’s detected,” Newman-Toker says. “These are frequent problems that have played second fiddle to medical and surgical errors, which are evident more immediately.”

He says experts have often downplayed the scope of diagnostic errors not because they were unaware of the problem, but “because they were afraid to open up a can of worms they couldn’t close.” (The research is available online at http://tinyurl.com/diagnosiserrors. The abstract is free, but there is a fee for accessing the entire study.)

“Progress has been made confronting other types of patient harm, but there’s probably not going to be a magic bullet solution for diagnostic errors because they are more complex and diverse than other patient safety issues,” Newman-Toker says. “We’re going to need a lot more people focusing their efforts on this issue if we’re going to successfully tackle it.”

Newman-Toker and his colleagues analyzed medical malpractice payments data from the National Practitioner Data Bank. They found that of the 350,706 paid claims, diagnostic errors were the leading type (28.6%) and accounted for the highest proportion of total payments (35.2%). Diagnostic errors resulted in death or disability almost twice as often as other error categories.

They also found that more diagnostic error claims were rooted in outpatient care than inpatient care (68.8% vs. 31.2%), but inpatient diagnostic errors were more likely to be lethal (48.4% vs. 36.9%). Most diagnostic errors were missed diagnoses, rather than delayed or wrong ones. Per-claim payments were highest in cases of serious neurologic harm, including quadriplegia and brain damage resulting in the need for lifelong care. Those payments, the researchers found, were higher even than for errors resulting in death.

Newman-Toker noted that among malpractice claims, the number of lethal diagnostic errors was roughly the same as the number that resulted in permanent, severe harm to patients. This quality suggests that the public health impact of these types of mistakes is probably much greater than previously believed because prior estimates are based on autopsy data, so they only count deaths and not disability, Newman-Toker says.


David E. Newman-Toker, MD, PhD, Associate Professor of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD. Telephone: (410) 614-1576. Email: toker@jhu.edu.