Diagnostic errors continue at a significant rate despite recent efforts to reduce them. New research identifies the three most common diagnostic errors and 15 specific conditions.

  • The research should help risk managers focus their patient safety efforts.
  • The most common claims do not necessarily represent the most common errors.
  • Any solution must involve improving clinical decision-making at the bedside.

Despite several years of attention from the medical community, diagnostic errors remain one of the largest threats to patient safety. Three disease categories account for nearly three-quarters of all serious harm from diagnostic errors, according to recent research.

Those categories are vascular events, infections, and cancers. The research was led by David Newman-Toker, MD, PhD, director of the Johns Hopkins Armstrong Institute Center for Diagnostic Excellence, who says risk managers and clinicians can use that information to more sharply focus their efforts to reduce diagnostic errors.

The research was based on an analysis of a malpractice insurance claims from CRICO’s Comparative Benchmarking System, representing 30% of all malpractice claims in the United States. Previous closed claim studies have indicated that diagnostic-related events are the single largest root cause of medical professional liability claims. An analysis from Coverys, a medical malpractice insurer based in Boston, revealed that diagnostic errors account for 33% of medical professional liability claims and 47% of indemnity payments.

In the Coverys research, most diagnostic errors occurred in outpatient settings, with 24% of diagnostic-related claims taking place in the ED and urgent care facilities. Another 35% of diagnostic errors occurred in non-ED outpatient settings, such as physicians’ offices or clinics. (The full report is available online at: https://bit.ly/2qlmVtz. For more on the report, see the story in the May 2018 issue of Healthcare Risk Management, available at: https://bit.ly/2MVWeYE.)

List of Conditions

In the research led by Newman-Toker, diagnostic errors were the “most common, most catastrophic, and most costly of medical mistakes.” For diagnostic errors leading to death or serious, permanent disability, misdiagnosed cancers accounted for 37.8%, vascular events for 22.8%, and infections for 13.5%.

The research also identified 15 specific conditions related to those three disease categories that together account for nearly half of all serious, diagnostic-related harm: stroke; sepsis; lung cancer; heart attack; venous thromboembolism; aortic aneurysm and dissection; arterial thromboembolism; meningitis and encephalitis; spinal infection; pneumonia; endocarditis; and breast, colorectal, prostate, and skin cancers. (The study is available online at: https://bit.ly/2NNSj1Z.)

There was some difference across patient demographics. In children and young adults, the most serious harms were from missed infections (27.6%) rather than vascular events (7.1%) or cancers (9.1%). Older adults had the opposite experience. Half of the high-severity harm cases related to diagnostic errors resulted in death and the other half caused permanent disability.

Risk Managers Are Aware

Researchers in diagnostic errors think of risk managers as already part of the solution, Newman-Toker says. Among healthcare professionals, risk managers are among the most in tune with this risk, he says, but this latest research can help them direct their prevention efforts more strategically.

“Risk managers know that diagnostic errors are a serious threat to patient safety, but what they may not know is how many of these errors are tied to the big three: vascular events, infections, and cancers,” Newman-Toker says. “The top five diseases in each of those three big buckets account for nearly 50% of claims related to diagnostic errors. That is more important in some sense than the three big buckets accounting for three-fourths of the claims, because diagnostic errors are one of those huge problems that can seem infinite.”

Knowing that those 15 diseases figure predominantly in diagnostic errors gives risk managers a roadmap for directing their efforts and resources, Newman-Toker says. He points out that the research focused on serious harm from diagnostic errors, rather than including all diagnostic errors that may be unfortunate but do not result in death, permanent disability, or serious harm.

With limited resources, patients have indicated that they are willing to ask the medical community to focus on diagnostic errors that are devastating, such as the loss or permanent disability of a loved one, rather than things that might cause suffering but are not as catastrophic, he says.

“For risk managers, that means that if you are going to invest in fixing these problems, you should invest in those 15 diseases. They are your top claim sources and they are likely to be your top public health problems,” Newman-Toker says. “Whatever quality improvement programs you support, whatever payment programs and incentives you suggest or research projects you fund, your focus should be on those 15 diseases.”

Research Looks at Serious Cases

The research emphasizes that diagnostic errors are among the most common and costliest threats to patient safety, says Paul Epner, MBA, CEO of the Society to Improve Diagnosis in Medicine.

“There are people who say diagnostic errors are a problem, but people do get better. even if their condition lasts a week longer until they got the right treatment, whereas this research looks at the very serious conditions,” Epner says.

Sometimes, diagnostic errors can escape the risk manager’s oversight when they are traced to a cognitive error, a clinician’s failure to recognize symptoms, and make the right judgment call, Epner says. Those cases often are diverted to the hospital’s peer review process, which may not directly involve the risk manager.

Some hospitals separate their peer review process and the root cause analyses in such a way that the true effect of diagnostic errors can be lost on the risk manager, Epner says. A key first step is to make sure you are tracking diagnostic errors properly.

“Many health systems don’t even have a category for diagnostic error. Things get tracked in other categories and you can find them if you dig deep enough and know where to look,” he says. “For a risk manager, if you look in your system and you don’t have a category for diagnostic error, then you’re not able to appropriately allocate resources to address the problem.”

Bias in Closed Claims

Newman-Toker notes that closed claims are a biased subset of all medical errors and harm events. They are not necessarily representative of all such events because only a small fraction lead to multiple claims. Several factors influence that fraction.

However, Newman-Toker says, his research compared the three disease categories accounting for nearly three-quarters of all serious harm from diagnostic errors in malpractice claims to their prevalence in clinical case series, reports of certain types of medical conditions that are noteworthy but not necessarily related to a malpractice claim.

“It shows the exact same total — three-fourths of all the serious harms in clinical practice are from the big three,” he says. “But it shows a very different weighting schema, with cancer cases much less prominent in clinical series than they are in claims. Vascular events and infections dominate with a greater percentage than cancer cases in clinical case series.”

That means cancer cases are overrepresented in claims, and the other two are underrepresented, he explains.

“That make some sense, because there is a paper trail with cancer cases and they unfold over time, with lots of opportunity to diagnose it. With a lot of vascular events, it’s a one-time thing with one shot at diagnosing it, and then it becomes a he-said/she-said about whether you should have diagnosed it,” Newman-Toker says. “Those suits are harder to bring, so we think a disproportionate number of them do not make it all through the system to become a claim. The lawyers are focusing on the cancer claims they think they can win.”

That issue is important to risk managers, Newman-Toker says, because they have to choose whether their patient safety efforts regarding diagnostic errors should focus on the category most likely to result in liability — cancer — or the issue that probably is a more common threat to patients — vascular and infection issues.

“You wouldn’t want to abandon any focus on cancer, but you might want to rebalance your portfolio in light of this information,” he says.

The causes of diagnostic error also should be a concern for risk managers, he says. The reasons these errors occur should drive any campaign to reduce them, but Newman-Toker says the medical community often takes a different approach.

“The politically correct thing to do in the diagnostic error world and the risk management world around this issue is to focus on solutions that feel like Mom and apple pie. You get things like better teamwork and more effective communication with patients,” he says. “But when we looked at the actual causes, far and away and in all three big buckets, the leader was clinical judgment. That’s the elephant in the room.”

That means one cannot solve the problem without improving clinical reasoning at the bedside, Newman-Toker says. “You’re spitting into the wind if you’re just trying to just fix communication gaps and teamwork problems. It’s true in other areas that if you fix those things you can solve the problem, like handwashing and sterile precautions for catheter insertions,” he says. “It works because everybody knew how to wash their hands; they just weren’t doing it. If they have the technical ability to do a thing but lack the motivation to do it, then fixing teamwork and culture will fix the problem.”

Join National Effort

But the root of diagnostic errors is different, he says. The technical ability to make the correct diagnosis, particularly in cases that are not obvious, is necessary to avoid these errors. That cannot be addressed with teamwork and communication, he says.

“The message for risk managers is you must address clinical reasoning at the bedside as part of your solution strategy. You don’t need to forgo teamwork and culture, but in this case you’re not going to solve the real problem that way,” Newman-Toker says.

Newman-Toker also says it is important for risk managers to be a part of the community addressing this issue, not just locally but on a national level by working groups such as the Society to Improve Diagnosis in Medicine.

“We want risk managers who are committed to this cause. This is a critical juncture where we need everyone to speak with one voice about how important this is,” he says. “Risk managers have been out there in the wilderness, the lone voice crying out. They need to join chorus with the newly woke members of the team.”


  • Paul Epner, MBA, CEO, Society to Improve Diagnosis in Medicine, Evanston, IL. Website: https://www.improvediagnosis.org.
  • David Newman-Toker, MD, PhD, Director, Johns Hopkins Armstrong Institute Center for Diagnostic Excellence, Baltimore. Phone: (443) 287-9593.