First medical diagnosis often incomplete or plain wrong, study finds

Bradley J. Fikes

When your doctor gives a diagnosis of a complicated disease, it often pays to get an independent second look, according to a study from Mayo Clinic published Tuesday.

Second medical opinions given at the famed medical institute most often result in a refined or totally new diagnosis, the study found.

In 21 percent of cases, Mayo Clinic doctors gave a completely different diagnosis than the original. The diagnosis was refined or extended in 66 percent of cases. In the remainder, the diagnosis was unaltered.

The referrals Mayo Clinic gets aren’t typical of all patients. They concern diseases that are difficult to diagnose, while the great majority of diagnoses are straightforward and never require a second opinion.

The study was led by James Naessens, a health care policy researcher at Mayo Clinic. It was published in the Journal of Evaluation in Clinical Practice. It can be found online at j.mp/2ndopinions.

Numerous studies have been performed on the accuracy of initial medical diagnoses and the value of second opinions, said Dr. Thomas Beckman, one of the study’s co-authors. This one differs from the others by using more complete patient information, including an in-person medical examination as part of the second opinion.

In general, patients seeking a second opinion should look for an academic medical center close to them, Beckman said. While second opinions add to medical bills, they can prevent even most costly consequences of a misdiagnosis.

The in-person component to a second opinion is critical, Beckman said. Doctors can glean much information about a patient’s health by being physically present with them, such as by reading their body language. And for a complete second opinion, tests need to be redone.

“So much of what we do depends on taking a history, performing a physical examination, and repeating studies we think might need repeating,” Beckman said. “That is all part of practicing medicine. Simply looking at outside records is not practicing medicine. It is a poor proxy of medicine itself. That’s one thing that might have made our study unique.”

Toughest cases

Researchers examined records of 286 patients seen from Jan. 1, 2009, to Dec. 31, 2010. Patients were referred from primary care providers to Mayo Clinic's General Internal Medicine Division in Rochester, Minnesota.

“Referrals to advanced specialty care for undifferentiated problems are an essential component of patient care,” the study concluded. “Without adequate resources to handle undifferentiated diagnoses, a potential unintended consequence is misdiagnoses resulting in treatment delays and complications leading to more costly treatments.”

The term “undifferentiated” refers to symptoms that are ambiguous or uncertain, fitting more than one disease. A wrong diagnosis causes harm to a significant proportion of patients, the study stated.

“Findings from autopsies indicate that diagnostic errors contribute to approximately 10 percent of patient deaths and diagnostic errors account for 6 to 17 percent of adverse events in hospitals,” it said.

Wrong diagnoses can lead to the wrong treatment, harming patients, the study stated, referring to a recent report by the National Academy of Medicine, “Improving Diagnosis in Health Care”.

And in 2016, a study on medical errors found they were the third leading cause of death. Reducing faulty diagnoses would presumably also reduce the total mortality from all medical errors.

Mayo Clinic often handles the most difficult cases, so it’s not surprising they would often provide refined or different diagnoses than the original, said Dr. Kenneth Roth, president of Sharp Community Medical Group.

“As a physician practicing in San Diego, I’m always delighted to have the ability to have the expertise that the Mayo Clinic offers to my patients,” Roth said. The medical group has about 230 primary care physicians and 570 specialists in private practices around San Diego County.

The nearest Mayo Clinic location to San Diego is in Phoenix, where it has a hospital.

San Diego’s high level of health care

Roth said he rarely refers to Mayo Clinic, because there’s a wealth of health care expertise in San Diego County, with its specialists, medical researchers and hospitals.

Most diagnoses are relatively straightforward and don’t require a second opinion, Roth said. Patients should trust their doctor in determining whether a second opinion is desirable.

“I’d say 99 percent of doctors know how to treat heart failure, emphysema, Crohn’s, colitis, acute myelocytic leukemia,” Roth said. “There’s standards of care for treating those kinds of conditions.

First, there’s the expertise available at his own medical group, Then for even more complex cases, San Diego County has prominent “super-specialists” in many fields.

But when the local experts can’t make a definitive diagnosis, then the resources of a group like Mayo Clinic are useful, he said.

“That ability to have that in-depth look and have all the specialty care focused and concentrated in a small community, really helps a physician who’s struggling to make a diagnosis,” Roth said.

Other areas of the country don’t have the level of expertise available in San Diego County, so they may depend more upon referrals outside their region. Roth said he experienced that in his early days as a doctor.

“I trained in northeastern Arizona, a place called Tuba City, and we did not have the resources there, for example MRIs, robots or all the technology San Diego has to offer,” he said. “So when you can’t make a diagnosis, you look for outside expertise, and move a little more quickly to a Mayo Clinic type of option.”