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Patient Safety Tip of the Week
January 10, 2023
Diagnostic
Errors in the ED
AHRQ recently published a study (Newman-Toker 2022) on
diagnostic errors in the emergency department that has garnered substantial
interest from the lay press. The study has been largely criticized in that some
of the data came from European or Canadian emergency departments, rather than
US emergency departments, and that it unfairly targets ED physicians. But the
authors make it very clear that the diagnostic error rates found in the ED are
very comparable to those found in hospital inpatient care or primary care.
We’ve long
criticized the landmark report “To Err Is Human” in that it sensationalized
statistics that garnered attention for a short period and ultimately did little
to improve patient safety over the next decade. So, let’s cast aside the
criticisms of the new AHRQ study, ignore the focus on statistics, and instead focus
on the important lessons learned from the study.
The emergency
department, by its very nature, is a high-risk venue. Interactions with
patients are generally for a short period of time, often done under time
pressure and multiple potential distractions. Most importantly, the clinician
doing the ED evaluation may never see that patient again. Ensuring a proper
handoff to the clinician who will next care for the patient is critical. Our current systems for care coordination are
not very good. We can’t tell you the number of times we hear a primary care
physician say “I didn’t even know {my patient} had
been in the ED”. Patients are often discharged from the ED before final imaging
reports are available and we’ve all seen patients “fall through the cracks”
when an important imaging finding is never communicated to someone who would
ensure follow-up. Particularly in small rural hospitals, lack of specialty
consultants may be a further problem. Add to all this the problem of
overdiagnosis and impact of the “diagnostic cascade” that can itself lead to
patient harm and add to healthcare expenditures.
The study was really
a systematic review and meta-analysis based on an extensive review of the
literature, encompassing 279 studies. An estimated 5.7% of all ED visits
had at least one diagnostic error. Estimated preventable adverse event rates
were 2.0% for any harm severity, 0.3% for any serious harms,
and 0.2% for deaths. That translates to
about 1 in 18 ED patients receiving an incorrect diagnosis, 1 in 50 suffering
an adverse event, and 1 in 350 suffering permanent disability or death. Again,
these rates are comparable to those seen in primary care and hospital inpatient
care.
So those are the
statistics. Yes, those are the ones garnering all the headlines in the lay
press (New York Times, Boston Globe, CNN, and multiple others). And the
statistics do little to help us improve patient safety. Rather, we must look at
the real opportunities to improve patient safety. The more important questions
to ask are “what are the serious conditions that are more likely to be missed?”
and “what are the presenting symptoms that often lead to missed diagnoses?”.
When seeing patients in any healthcare venue, the two most important questions
we usually ask ourselves are “What could I be missing?” and “What’s the
most serious thing I could be missing?”.
The top 15 clinical conditions associated with serious
misdiagnosis-related harms, accounting for 68% of serious harms, were (in order
of frequency):
·
stroke
·
myocardial infarction
·
aortic aneurysm and dissection
·
spinal cord compression and injury
·
venous thromboembolism
·
meningitis and encephalitis
·
sepsis
·
lung cancer
·
traumatic brain injury and traumatic
intracranial hemorrhage
·
arterial thromboembolism
·
spinal and intracranial abscess
·
cardiac arrhythmia
·
pneumonia
·
gastrointestinal perforation and rupture
·
intestinal obstruction
The top five conditions noted above account for 39 percent
of serious misdiagnosis-related harms.
But even knowing the clinical conditions most often missed
is not enough. Patients don’t come to the ED with a complaint “possible spinal
cord compression”. While it is nice to know the conditions most often missed,
it would also be nice to know which diagnoses made were most often in error.
For example, if it turns out a diagnosis of “vestibular neuritis” was erroneous
15% of the time, that might prompt ED clinicians to always think twice any time
they consider such a diagnosis. And our focus should be on the presenting
symptoms most often associated with missed diagnoses.
The AHRQ study did find that clinical presentation was
important. For example, the average rate for missed stroke was 17% but it
was 40% when the presenting symptom was dizziness/vertigo vs. 4% when the
presenting symptom was weakness. The authors found that nonspecific, mild,
transient, or “atypical” symptoms frequently contributed to missed diagnoses.
In fact, atypical or non-specific symptoms were the strongest and most
consistent predictors of increased risk for a missed diagnosis across diseases
studied.
The authors provided a table with the most common “atypical”
presenting symptoms and their related misdiagnosed diseases:
|
Abdominal pain |
Myocardial infarction, aortic aneurysm/dissection, appendicitis,
diverticulitis, ovarian disease, gallbladder pathology, cancer |
|
Back pain |
Spinal abscess or other spinal cord compression, myelitis,
aortic aneurysm/dissection |
|
Dyspnea/shortness of breath |
Myocardial infarction, aortic aneurysm/dissection |
|
Fever |
Sepsis, aortic aneurysm/dissection (aortitis) |
|
Headache |
Stroke, (other diseases with headaches as a more “typical”
presentation include subarachnoid hemorrhage, meningitis/encephalitis, raised
intracranial pressure, and giant cell arteritis) |
|
Syncope/fall |
Myocardial infarction, aortic aneurysm/dissection, venous
thromboembolism, stroke |
|
Altered mental status/confusion |
Stroke, sepsis |
|
Dizziness/vertigo |
Stroke |
|
Fatigue/malaise/generalized weakness |
Myocardial infarction, stroke, sepsis |
|
Gait disturbance |
Stroke |
|
Nausea/vomiting |
Stroke, appendicitis, myocardial infarction |
Atypical or non-specific symptoms were the strongest and
most consistent predictors of increased risk for a missed diagnosis across
diseases studied.
Patient age, gender, and race may impact error rates. For
example, older age increases risk of missed appendicitis, while younger age
increases risk of missed stroke 6.7-fold. The lay press (Medaris
2022) recently highlighted the latter problem, describing 3 patients
in their 20’s whose strokes were misdiagnosed as being due to migraine or drugs.
Female sex and non-White race were often associated with
important (20–30%) increases in misdiagnosis risk in the AHRQ study. There was
also significant variation by hospital (for example, the rate of missed
myocardial infarction varied from 0% to 29% across hospitals within a one study). Other notable predictors of misdiagnosis
included care provided by less experienced clinicians, at non-teaching
hospitals, with high ED discharge fraction, and during off hours. The
diagnostic performance gap with academic (teaching) ED’s having lower false
negative rates than community (non-teaching) ED’s was a fairly
consistent finding, but it is unknown whether lower academic
false-negative rates were achieved through greater overall diagnostic accuracy
or by favoring overutilization, leading to arbitrarily greater admission
fractions and resulting in higher false-positive rates.
The AHRQ study also cites previous work from malpractice claims
on factors contributing to ED diagnostic error. Such factors include failure/delay
in ordering diagnostic test; lack of/inadequate patient assessment with
premature discharge; narrow diagnostic focus in patient assessment with failure
to establish differential diagnosis; failure to appreciate and reconcile
relevant signs, symptoms, or test results; failure/delay in obtaining a
consultation or referral; misinterpretation of diagnostic test studies (e.g.,
X-rays); issues related to lack of health insurance; inadequate communication
among providers regarding the patient’s condition; off-hours care (weekend,
night shift, or holiday); inadequate history or physical examination.
Of course, we always need to balance the risk of
misdiagnosis against the risk of overdiagnosis or unintentionally initiating
the “diagnostic cascade”. For example, though stroke was often misdiagnosed
when vertigo/dizziness was a presenting symptom, we certainly don’t want every
patient with vertigo or dizziness to get a CT scan or MRI scan. We know that
the diagnostic cascade not only adds to the cost of healthcare but may also
lead to unnecessary procedures that, in turn, may lead to patient harm.
From the studies done on diagnostic error in the ED, it is also
difficult to understand the likely role of fatigue, which we know increases
error rates in a variety of venues. There is also one other consideration never
assessed in these studies. We’ve often cited a study on shift workers in fields
other than healthcare (Folkard 2003)
which showed that the risk of incidents increased each consecutive day worked.
For example, on average for night shifts risk was 6% higher on the second
night, 17% higher on the third night, and 36% higher on the fourth night (for
morning/day shifts the corresponding risks were 2%, 7% and 17%). There’s little
reason to think that such trends might not also occur in healthcare,
particularly in the ED where long consecutive-day shifts are common.
The AHRQ study wasn’t the only recent study on diagnostic
errors in the ED. Baartmans et al. (Baartmans
2022) studied 23 serious error event reports of diagnostic events in
emergency departments of Dutch general hospitals and identified human errors. Twenty-one
reports contained a diagnostic error, in which the authors identified 73 human
errors. These were mainly based on intended actions (n = 69) and could be
classified as mistakes (n = 56) or violations (n = 13). Most human errors
occurred during the assessment and testing phase of the diagnostic process.
Similar to the AHRQ report, most
prevalent missed or delayed final diagnoses were cardiovascular (n = 11) or
neurological (n = 5) conditions, such as aorta dissection, ruptured abdominal
aortic aneurysm, subarachnoid hemorrhage, and spinal cord injury. They found
that diagnostic errors occurred most often in the assessment and testing domains.
Other human errors sometimes occurred during referral or consultation, history
taking, the physical exam, follow-up, and at access to care or presentation. Most
human errors involved a failure or delay in recognizing the urgency of the
situation or putting too much weight on a competing or coexisting diagnosis (for
example, the working diagnosis of a migraine disrupted the search for other
causes of the symptoms of a patient with a subarachnoid hemorrhage). Other
recurring themes were the failure or delay to consider a diagnosis, failed or
delayed follow-up of (abnormal) test results, failure or delay in ordering needed
tests, wrong test orders, and failure or delayed communication or follow-up of
a consultation.
The authors note that hospitals
seldom propose overarching interventions to support the diagnostic process, for example, evidence-based strategies to improve specific knowledge, reforming
training methods, structural
feedback and reflection on diagnostic
discrepancies, implementation of
diagnostic decision support systems to improve diagnostic calibration, or implementing team-based diagnosis. They also note that system-aimed interventions (e.g., lowering
work pressure and crowding in the ED,
improving patient safety culture, teamwork
interventions, and cultural
aspects) are also rarely
proposed, while these types of
recommendations may have a
better chance of being effective in preventing similar cases and to improve diagnostic safety.
Diagnostic error remains our greatest patient safety
challenge. It’s an area for which we’ve had the fewest solutions to date, and it
applies to every healthcare venue, not just the ED. Sensationalizing the statistics
is not likely to lead to any productive changes. Rather, focusing on the nature
of the errors and factors contributing to them is much more likely to lead to
productive changes. In that regard, the AHRQ study is a useful beginning.
References:
Newman-Toker DE, Peterson SM, Badihian S, et al. Diagnostic Errors in the Emergency
Department: A Systematic Review. Comparative Effectiveness Review No. 258.
(Prepared by the Johns Hopkins University Evidence-based Practice Center under
Contract No. 75Q80120D00003.) AHRQ Publication No. 22(23)-EHC043. Rockville,
MD: Agency for Healthcare Research and Quality; December 2022
Medaris
A. Doctors dismissed these 3 young people's symptoms as migraines or
drug-related — but they were really having strokes. Insider 2022; Dec 26, 2022
https://www.insider.com/doctors-dismissed-young-peoples-strokes-as-drugs-alcohol-migraines-2022-11
Folkard S, Tucker P. Shift work, safety and productivity. Occupational Medicine 2003; 53:
95-101
Baartmans MC, Hooftman
J, Zwaan L, et al. What Can We Learn From In-Depth
Analysis of Human Errors Resulting in Diagnostic Errors in the Emergency
Department: An Analysis of Serious Adverse Event Reports. Journal of Patient
Safety 2022; 18(8): e1135-e1141
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