How Common is Misdiagnosis?
Data source:
http://www.wrongdiagnosis.com/intro/common.htm
Although there is a general feeling that
misdiagnosis is quite common, with many people giving anecdotal
accounts of their own experiences, it is difficult to get exact
data. Whereas there are many studies of adverse drug events and
nosocomial infections,
there is a relative lack of misdiagnosis studies.
A study of Patient Safety Incidents (PSIs) by HealthGrades found
that "Failure to Rescue", meaning failure to diagnose and treat
in time, was the most common cause of a patient safety incident,
with a rate of 155 per 1,000 hospitalized patients.
Unfortunately, the study did not further break down statistics
into the types of misdiagnosis, delayed diagnosis or other
factors. 1
The National Patient Safety Foundation (NPSF)
commissioned a phone survey in 1997 to review patient opinions
about medical mistakes. Of the people reporting a medical
mistake (42%), 40% reported a "misdiagnosis or treatment error",
but did not separate misdiagnosis from treatment errors.
Respondents also reported that their doctor failed to make an
adequate diagnosis in 9% of cases, and 8% of people cited
misdiagnosis as a primary causal factor in the medical mistake.
Loosely interpreting these facts gives a range of 8% to 42% rate
for misdiagnoses.
Misdiagnosis rates in the ICU or Emergency
Department have been studied, with rates ranging from 20% to
40%. These misdiagnosis rates are likely to be higher than the
overall health care misdiagnosis rate because of the
time-critical and serious nature of the diagnosis under these
crisis conditions.
Malpractice and misdiagnosis:
Another interesting fact is that a large proportion of
malpractice cases are based on misdiagnosis or delayed treatment
of serious conditions.
Davenport
(2000) lists the top five malpractice-risk conditions in order
of prevalence as myocardial infarction, breast cancer,
appendicitis, lung cancer and colon cancer, and notes that
almost all suits are cases of misdiagnosis or mismanaged
diagnostic tests leading to delayed treatment. Myocardial
infarction and appendicitis are likely to be related to
emergency department visits, whereas the three litigation-prone
types of cancers are more common in general physician work.
Misdiagnosis in the emergency department:
The rates of misdiagnosis in the emergency department or ICU
have been studied. The majority of lawsuits involved the ED and
of these, the majority involved delayed treatment and therefore
presumably related to misdiagnosis. One study found a rate of
20% of misdiagnosis in the ICU. Other studies have found that it
is relatively common for serious conditions such as
acute myocardial infarction
(heart attack),
stroke,
pulmonary embolism,
meningitis, or
appendicitis to be
misdiagnosed in emergency care. For example, non-typical
presentations such as a young person or a woman having a heart
attack are less likely to be correctly diagnosed. Furthermore,
an ECG test does not rule out a heart attack even if it is
normal, and some physicians rely too heavily on this test.
Appendicitis is another common and serious
misdiagnosis in the ED. Initial misdiagnosis rates of
appendicitis in children are high, ranging from 28% to 57% under
12s to almost 100% misdiagnosis for appendicitis in infants (Rothrock
et al, 2000).
Misdiagnosis and biopsy:
Pathology slide tests involve a workup of a sample onto a slide
and then a manual viewing by a pathologist, or more commonly a
technician. They are commonly used to identify abnormal cells,
such as in cancers. This inherently human process has a clear
risk of error and can lead to misdiagnosis. For example, in a
December 1999 study of 6,171 slides,
Johns
Hopkins
Hospital
in Baltimore
found a 1.4% error rate in pathology tests in patients referred
for cancer treatment. Of the 86 total misdiagnoses, 20 had
benign tumors misdiagnosed as malignant and presumably received
unnecessary cancer treatment. An earlier Johns Hopkins study of
prostrate cancer biopsies found an error that ruled out cancer
in six out of 535 cases.
Misdiagnosis and autopsy studies:
One useful way to detect misdiagnosis is to perform an autopsy,
and then compare the original diagnosis with that found at
autopsy. Various studies have found major differences, with
discrepancy rates as high as 40% in the Medical ICU (CHEST,
February 2001). This rate of 40% in the ICU is undoubtedly
higher than the rate for general medicine because of the
difficult and often multifactorial nature of serious ICU cases.
Unfortunately, autopsy rates are declining for various reasons
and the opportunity to measure misdiagnosis in this way is
reduced.
TopReferences
·
Patient Safety in American Hospitals, July 2004, HealthGrades
Quality Study, HealthGrades,
http://www.healthgrades.com/media/english/pdf/HG_Patient_Safety_Study_Final.pdf
·
National Patient Safety Foundation at the AMA: Public Opinion of
Patient Safety Issues, Louis Harris & Associates, September
1997.
·
Institute of Medicine (IOM), "To Err Is Human: Building a Safer
Health System", 2000,
online.
·
John Davenport, MD, JD, Documenting High-Risk Cases to Avoid
Malpractice Liability, Family Practice Management, October 2000
·
Joseph D. Kronz, William H. Westra, and Jonathan I. Epstein,
Mandatory Second Opinion Surgical Pathology at a Large
Referral
Hospital, Cancer: Dec. 1,
1999, vol. 86, no. 11, pp 2426-2435. (Johns Hopkins study)
·
Steven G. Rothrock MD, Joseph Pagane MD, Annals of Emergency
Medicine, Vol. 36, No. 1, July 2000.
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