Misdiagnosed: The Causes, Effects and (Possible) Remedies of a Medical Malady

By the time Jennifer Rufer discovered that she had been misdiagnosed at age 22 with a rare form of cancer, it was too late. She had already needlessly suffered through three years of chemotherapy and surgeries, including a hysterectomy that left her unable to live the life she imagined as a mother. It all started when she began having irregular menstrual bleeding and was given a routine pregnancy test that came back positive. The problem: While she was producing high levels of human chorionic gonadotropin (HCG), which happens when a woman is pregnant, there was no fetus — which is sometimes a sign of a rare form of cancer, a gestational trophoblastic tumor. Yet, although specialists were unable to find a tumor, she was diagnosed with cancer and immediately started on chemotherapy. But, after months of debilitating treatments, repeated pregnancy tests (using the same lab test) continued to show her HCG levels at between 250 and 350, compared to a normal level of about five. The next step was a hysterectomy, followed by additional surgeries, from which tissue samples showed no evidence of cancer. The stunning revelation: She never had cancer to begin with. The pregnancy test was giving a false positive result.

A jury ruled that the hospital that treated Rufer and the maker of the pregnancy test were both at fault, and unanimously awarded Rufer $15 million for pain and suffering and $452,000 more for economic damages, including lost wages and the costs of having children using a surrogate mother. But, this in no way makes up for what she endured due to misdiagnosis — one of many types of misdiagnoses that occur far too often. Discovering why misdiagnoses happen and what can be done to reverse their trend, which shows no sign of decreasing, is more important than ever.

Defining Misdiagnosis

There are three major categories of medical misdiagnosis. A false positive is a misdiagnosis of a disease that is not actually present. A false negative is a failure to diagnose a disease that is present. And, equivocal results are an inconclusive interpretation without a definite diagnosis.¹

Misdiagnosis occurs in many ways. For instance, it can occur due to failure to properly diagnose an underlying condition, the cause of a health condition, the subtype of a properly diagnosed disease such as diabetes or heart disease, a condition related to the original disease, or any complications that the original disease caused. It also can result when there is a diagnosis of the wrong disease, a diagnosis of an illness when the patient is actually healthy, or when the diagnosis is missed or delayed.²

No Rare Occurrence

According to an analysis of autopsy data, the five most commonly misdiagnosed diseases (based on relative incidence) are pulmonary emboli, myocardial infarctions, aortic aneurysms, neoplasms and cardiovascular disease. And, in an analysis of malpractice data, the five most commonly misdiagnosed diseases were breast cancer, colorectal cancer, infections, skin cancer and fractures.³

With all of the diagnostic tools available to modern medicine, misdiagnosis should be a rare occurrence. But, it’s not. Studies of autopsies have shown that doctors seriously misdiagnose fatal illnesses 20 percent of the time, resulting in millions of patients being treated for the wrong disease.⁴ For instance, in a study of autopsies published in the Mayo Clinic Proceedings comparing clinical diagnoses with postmortem diagnoses for medical intensive care unit patients, in 26 percent of cases, a diagnosis was missed clinically. If the true diagnosis had been known prior to death, it might have resulted in a change in treatment and prolonged survival in most of these misdiagnosed cases.³

Medical imaging is another area where rates of misdiagnosis are high. Radiology-specific studies have shown significant error rates, with the failure to detect abnormalities in 25 percent to 32 percent of cases where disease was present (false negative) and incorrectly diagnosing diseases in 1.6 percent to 2 percent of cases that were actually normal (false positive).³

Misinterpretation and difficult-case disagreement rates also are higher for more advanced modalities. In one study, substantial disagreement between radiologists when using MRI for diagnosis in patients suspected of lumbar disc herniations was present in 30 of 59 patients (51 percent).³

While this is just a sampling of the astonishing rates of medical misdiagnosis, the more astonishing fact is that the rate has not really changed since the 1930s.

Error, Oversight or Apathy?

Why does misdiagnosis occur? The most common causes of misdiagnosis are a diagnostic “blind spot,” such as a conscious decision not to pursue a clinical finding, failure to account for a symptom or sign, atypical presentations and/or inadequate follow-up of abnormal laboratory findings. In addition, the most common factors leading to medical errors include failure to obtain a proper medical history, order the appropriate diagnostic tests or provide adequate follow-up. In about 40 percent of most malpractice cases, the physician failed to issue a proper follow-up plan, perform an adequate physical examination or interpret a diagnostic test correctly. What’s especially interesting is that about three-quarters of cases are due to failures in judgment, half are due to lack of vigilance or memory and only one-quarter are due to negligence itself.³

Other reasons for misdiagnosis include failing to pay attention or respond to a patient’s complaints or symptoms, failure to refer a patient to a specialist in a timely manner and familiarity with only the most common of the approximately 20,000 human diseases.² While most patients trust that their physician has enough skill and knowledge to locate their health problem and take the necessary steps to fix it, most doctors are not familiar with every health condition that exists. It’s simply not possible to know how to treat every infection and disease under the sun. Plus, some conditions are rare and less likely to occur in patients, and some medical conditions have similar symptoms.⁵

A final reason for misdiagnosis could be that “under the current medical system, doctors, nurses, lab technicians and hospital executives are not actually paid to come up with the right diagnosis. They are paid to perform tests and to do surgery and to dispense drugs.”³ Therefore, healthcare professionals may have the best of intentions, but they have little economic incentive to spend time double-checking their instincts, and hospitals have little incentive, other than that threat of malpractice suits, to give them the tools to do so.

Effects of Misdiagnosis

Misdiagnosis can cause major problems for patients, healthcare professionals and organizations, and insurance providers.

For patients, quality of care is a big issue. Getting a false positive diagnosis, such as in Rufer’s case, can result in unnecessary treatments and even surgery before discovering they don’t have the diagnosed disease. With a false negative diagnosis, the undetected illness can cause the patient’s condition to deteriorate to the point where more extensive intervention becomes necessary with the increased risk of a poor outcome.¹ And a delayed diagnosis can result in no treatment at all.

Joanne Pease understands the consequences of a delayed diagnosis very well. When Pease’s first-born son, Curtis, was given live vaccines, he contracted the measles. Because physicians failed to test him for immune deficiency, it was unknown why he had contracted the disease from the vaccine. And, when her second son, Jeff, was born, Pease had concerns that the same thing could happen. The doctors, however, told her it wasn’t likely and recommended Jeff be vaccinated. After the second dose of polio vaccine, Jeff got very sick. He tested positive for polio, and then both sons were diagnosed with X-linked agammaglobulinemia (XLA), a primary immune deficiency. Jeff was left with a poorly functioning and very short leg requiring years of painful surgeries and therapies. Had Curtis been tested and diagnosed in infancy, Jeff would have been as well, sparing him from life-long impairment.

Anxiety and distress in patients also can be amplified with misdiagnosis. They may worry when an illness is not improving despite treatment, or when a disease progresses to a serious stage because necessary care was delayed. Patients also are concerned about lost income and mounting costs for prolonged treatments or repeated testing as a result of diagnostic errors or equivocal interpretations.¹

Physicians often share patients’ anxiety in such cases. Most physicians have the utmost concern for their patients; they uphold the medical creed to “first, do no harm.” But, the rate of misdiagnoses has caused concern among many patients, and this reflects not only on physicians’ confidence to correctly diagnose, but their ability to reassure their patients that their diagnoses are correct. In fact, a YouGov survey commissioned in 2005 by The Isabel Medical Charity revealed that 60 percent of people fear illnesses will not be correctly diagnosed when they visit their general practitioner. A third of the respondents had directly experienced or knew someone who had experienced a medical error, with 57 percent of the mistakes due to misdiagnosis.⁶

In 2004, a total of $4.2 billion was paid in medical malpractice lawsuits, with the highest payments (and the most common type of lawsuits) related to misdiagnosis, failure to diagnose or delayed diagnosis.³ Aside from lawsuits, insurance companies often are faced with higher payouts to healthcare organizations due to misdiagnosis. For instance, if patients fail to get the treatment they need, resulting in more severe illness, the costs will be even greater. In one typical case, a patient who was not properly diagnosed with a primary immune deficiency, which required treatment with intravenous immune globulin (IVIG), ended up in the hospital with a severe case of pneumonia, which ultimately cost the insurance company an additional $75,000, on top of the cost of IVIG treatments she eventually received.

Curbing the Persistent Problem

With almost no change in the rate of misdiagnoses over the years, what can be done to curb this persistent problem? For one, the need for a proper history and physical should be stressed. And policies, procedures and systems that can reduce the most common errors that lead to misdiagnosis should be instituted.³

One such system could be a pay-for-performance program to give physicians more economic incentive to decrease the number of misdiagnoses. Such a system was developed by Mark B. McClellan, MD, PhD, administrator for the Centers for Medicare and Medicaid Services, and is supported by the Isabel Medical Charity. The software, called Isabel, allows doctors to type in a patient’s symptoms and, in response, gives a list of possible causes. It is in use by Medicare, and a few insurers are also experimenting with it. And, while it doesn’t replace doctors, it does make sure they consider some unobvious possibilities that they may not have seen since medical school. 4 Some U.S. physicians have been quick to reap the benefits from the Isabel system, and five top children’s hospitals in the U.S. have already adopted the pediatric version. 6 Yet many have not adopted the system, perhaps because of its cost, which is $80,000 a year for a typical hospital and $750 a year for an individual doctor. But, then, misdiagnosis costs far more.

Familiarization with the commonly misdiagnosed conditions and the factors that lead to misdiagnosis also would help greatly. This could include continuing medical education courses that educate physicians about the critical breakdown points leading to misdiagnosis. Primary care physicians, in particular, would benefit from this type of education since they are usually the first physician that the patient presents to with their symptoms.

Familiarity with specific disease diagnoses and more frequent referrals to specialists also would help. Extensive research has demonstrated the relationship between case volume and patient outcome for a variety of medical conditions and procedures. Case volume refers to the number of specific types of diagnoses handled by a particular physician or healthcare organization (i.e., their familiarity with the disease diagnosis). One review of 128 studies examined 40 conditions or procedures, and found a statistically significant relationship between higher case volumes and better clinical outlines in 80 percent of those cases.

Another study examined the mammographic interpretation sensitivity demonstrated by individual radiologists. High sensitivity indicated the detection of a high percentage of true positive breast cancer cases. Radiologists who read more than 300 mammograms per month detected an average of 78.6 percent of cancers, compared with 71.5 percent found by radiologists who read 100 or fewer per month. In essence, the highervolume, more experienced radiologists were more likely to detect a cancer with the mammogram.¹

The Need for Greater Attention

Joseph Britto, a former intensive-care doctor, compares medicine’s attitude toward mistakes with the approach the aviation industry takes. According to Britto, at the insistence of pilots who have the ultimate incentive not to mess up, airlines have studied their errors and nearly eliminated crashes. “Unlike pilots,” he says, “doctors don’t go down with their planes.”⁴

One of the reasons that the rate of misdiagnoses has yet to decrease could be a lack of attention from the public. The United States healthcare system has lagged behind most other industries regarding the attention paid to ensuring safety, and the comparison with the airline industry is a good one. For example, the aviation industry has focused on producing a safety system since the 1940s, with more public attention centered on improving safety in the aviation industry than on healthcare — despite the higher risk of injury or death as a result of medical error versus being involved in an airplane crash. Media coverage seems to have been a major factor that encouraged safety improvements within the aviation industry.¹ Could that be the answer for the healthcare industry, too?