New test spots more lung clots but seems to result in overdiagnosis

July 2, 2013, British Medical Journal

A new diagnostic test to detect pulmonary embolism (a blockage of the main artery of the lung) misses fewer clots, but seems to result in overdiagnosis, warn experts in BMJ today.

The introduction of CT pulmonary angiography has been associated with an 80% rise in the detection of in the US, but with little change in .

Professor Renda Soylemez Wiener and colleagues argue this is evidence of overdiagnosis. They say some patients are helped, but many are harmed by the of unnecessary treatment.

This article is the first of a series looking at the risks and harms of overdiagnosis in a range of common conditions. The series, together with the Preventing Overdiagnosis conference in September, are part of the BMJ's Too Much Medicine campaign to help tackle the threat to health and the waste of money caused by unnecessary care.

Pulmonary embolism has been described as one of the most commonly missed deadly diagnoses. Until recently, ventilation-perfusion (VQ) scanning was the first line test, but a new technology introduced in 1998 – CT pulmonary angiography – offered higher resolution and more definitive results.

Using national US data, the authors show an 80% rise in incidence of in the eight years after CT pulmonary angiography was introduced (from 6.2 per 100,000 to 112.3 per 100,000 US adults).

Despite this, deaths from pulmonary embolism in the US population changed little (from 12.3 to 11.9 per 100,000), while in-hospital deaths decreased by a third (from 12.1% to 7.8%), suggesting that the extra emboli being detected are less lethal.

Data also show a substantial increase in complications from anti-clotting treatment, as well as fear and anxiety for patients following diagnosis and treatment.

The authors stress that inferring overdiagnosis by observing "has limitations" but say "its strength lies in its representativeness of the population and reflection of actual clinical practice."

Addressing the problem of overdiagnosis is challenging, and the answer is not simply to do less testing, they write. Instead, they suggest clinicians test (and subsequently treat) more selectively and consider alternative tests such as VQ scanning and ultrasound when appropriate.

"Pulmonary embolism is unquestionably an important cause of death, and rapid diagnosis and treatment can be life saving," they write. But the diagnostic zeal and technological advances meant to improve outcomes of patients with pulmonary embolism are double edged swords: some patients are helped, but many are harmed through overdiagnosis and overtreatment."

They conclude: "To improve outcomes for all patients, we need to learn more about which small emboli need treatment."

In an accompanying editorial, BMJ editors and others involved in the drive to prevent overdiagnosis say there is an urgent need to do better at identifying and spurring debate on the growth in unhelpful diagnosis and unnecessary treatment.

They believe we should be careful not to label risk factors as diseases and get better at sharing uncertainty with about disease definitions, the risks and benefits of testing, and the consequences of different treatment options.

They conclude: As countries struggle with rising health care costs, the economic downturn, and the challenge of providing equitable care for all, it's time to find ways to safely and fairly wind back the harms of too much medicine.

Explore further: Evidence of over-diagnosis of pulmonary embolisms as a result of CTPA

More information: www.bmj.com/cgi/doi/10.1136/bmj.f3368

Related Stories

Evidence of over-diagnosis of pulmonary embolisms as a result of CTPA

May 9, 2011
Researchers from Boston University School of Medicine (BUSM) have found that computed tomography pulmonary angiography (CTPA), meant to improve detection of life-threatening pulmonary embolisms (PE), has led to over-diagnosis ...

Asthmatics at increased risk of pulmonary embolism

December 19, 2012
People with asthma have an increased risk of pulmonary embolism, according to new research.

Clot-busters safe for treating moderate pulmonary embolism

March 27, 2012
Pulmonary embolism -- the sudden blockage of an artery in the lung -- is estimated to cause over 100,000 deaths each year in the U.S. Although thrombolytics, or "clot-buster" drugs, are currently reserved to treat only the ...

MRI techniques improve pulmonary embolism detection

March 19, 2012
New research shows that the addition of two magnetic resonance imaging (MRI) sequences to a common MR angiography technique significantly improves detection of pulmonary embolism, a potentially life-threatening condition ...

For embolism patients, clot-busting drug is worth risk

February 21, 2013
When doctors encounter a patient with a massive pulmonary embolism, they face a difficult choice: Is it wise to administer a drug that could save the patient's life, even though many people suffer life-threatening bleeding ...

Recommended for you

Study ends debate over role of steroids in treating septic shock

January 19, 2018
The results from the largest ever study of septic shock could improve treatment for critically ill patients and save health systems worldwide hundreds of millions of dollars each year.

New approach could help curtail hospitalizations due to influenza infection

January 18, 2018
More than 700,000 Americans were hospitalized due to illnesses associated with the seasonal flu during the 2014-15 flu season, according to federal estimates. A radical new approach to vaccine development at UCLA may help ...

Flu may be spread just by breathing, new study shows; coughing and sneezing not required

January 18, 2018
It is easier to spread the influenza virus (flu) than previously thought, according to a new University of Maryland-led study released today. People commonly believe that they can catch the flu by exposure to droplets from ...

Zika virus damages placenta, which may explain malformed babies

January 18, 2018
Though the Zika virus is widely known for a recent outbreak that caused children to be born with microencephaly, or having a small head, and other malformations, scientists have struggled to explain how the virus affects ...

Certain flu virus mutations may compensate for fitness costs of other mutations

January 18, 2018
Seasonal flu viruses continually undergo mutations that help them evade the human immune system, but some of these mutations can reduce a virus's potency. According to new research published in PLOS Pathogens, certain mutations ...

Study reveals how MRSA infection compromises lymphatic function

January 17, 2018
Infections of the skin or other soft tissues with the hard-to-treat MRSA (methicillin-resistant Staphylococcus aureus) bacteria appear to permanently compromise the lymphatic system, which is crucial to immune system function. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.