The sudden cardiac death of a young athlete causes extreme distress and sorrow.
Tragedy can induce simple thinking: Modern medicine should be able to identify the kids with heart disease before they die. If we take the time, hire the experts, spend the money, and screen all these kids—with both electrocardiograms (ECGs) and echocardiograms—then we will have no more tragedy.
In essence, a group of esteemed sports cardiologists in the United Kingdom did just that. Their findings have once again shown that the admirable idea of screening for disease comes fraught with the snags of reality.
Sanjay Sharma, MD, and a group of researchers from the St George's University of London took advantage of an ideal situation to study the incidence and causes of sudden death in adolescent soccer players. The authors harnessed data from the mandatory cardiac screening program of the English Football Association. Since 1996, more than 11,000, mostly male, athletes, aged 15 to 17 years, completed a health questionnaire, physical exam, ECG, and echocardiogram. Only true experts read the ECGs and echocardiograms. The kids were then followed throughout their time in the football association.
Sharma wrote in an email that the most rewarding aspect of the study was that they had a well-defined cohort where the numerator (number of deaths) and the denominator (the whole cohort throughout the follow-up period) was known. This, he pointed out, was "different from previous studies whose methodologies have been flawed by using social media and insurance claims, for example, to identify the numerator and rough estimates for a denominator."
The Main Findings
After studying more than 11,000 kids, they found 42 (0.38%) had cardiac diseases capable of causing sudden death. The majority of them had Wolff-Parkinson-White (WPW) (n = 26; 62%).
Only 2 of these 42 patients had symptoms; 36 had an abnormal ECG and 12 had abnormalities on echo.
Significant heart disease not typically associated with sudden death (eg, valvular disease or septal defects) was noted in 225 or 2% of the teenage athletes.
During the 20-year period (more than 118,000 person years), 23 kids died, 8 of them from cardiac causes. The researchers had autopsies on all cardiac deaths—7 were from cardiomyopathy.
Six of the 8 kids who died had completely normal cardiovascular screens. The authors confirmed the normal ECG and echo findings by two independent readers.
The overall incidence of sudden death was approximately 1 in 14,800 person-years or 6.8 per 100,000 athletes.
The researchers estimated costs using UK National Health Service prices. To screen the more than 11,000 athletes cost $3.8 million. The cost of further testing and treatment of 830 athletes with abnormal findings on screening brought this figure up to $4.3 million.
This study makes me think of the Karl Popper quote: "The more we learn about the world, and the deeper our learning, the more conscious, specific, and articulate will be our knowledge of what we do not know, our knowledge of our ignorance." 
Yes, these findings deepen our knowledge of heart disease in the young athlete, but they also expose how little we know about predicting the future.
A disease incidence of 0.38% means 99.6% of the population does not have disease. This analysis did not address sensitivity and specificity, but screening for diseases with this low an incidence will lead to many healthy individuals wrongly diagnosed with disease.
Numbers tell the story. Let's say we force screening on 100,000 young athletes. That means 99,600 will not have the disease.Even if we assume a generous 95% specificity of the screening test, nearly 5000 kids will be falsely diagnosed with heart disease (99,600 people without disease × 0.05).
Is mislabeling hundreds or thousands of young people with disease, and potentially denying them a lifetime of athletics or exposing them to the risks of further testing, worth finding a small number of kids with disease? Remember, too, that few screening programs can include the degree of expertise used in this study.
The authors confirmed a very low absolute incidence of sudden death in adolescent soccer players—although their observed rate of 6.8 per 100,000 is higher than in previous studies.[3,4] Still, playing sports looks no more dangerous to adolescents than driving does (7 deaths from road traffic accidents vs 8 deaths from cardiac causes).
Competing risks for death expose the folly of screening. The reason cancer screening in adults does not lower overall mortality is that even if the screening test could deliver lower disease-specific death rates, there are many other ways to die. The same goes for the soccer players. Two thirds of the deaths in this cohort were from noncardiac causes.
It also could be argued that finding 42 kids with life-threatening conditions plus 225 kids with significant but not deadly disease is a good thing because these diagnoses led to therapy. Of course, without proper randomized trials, we don't know whether early detection of these abnormalities improved outcomes. For instance, half the kids with serious disease had WPW. The evidence base supporting early intervention in asymptomatic patients with WPW comes from a tiny single-center study.
Most important, the authors have exposed the sobering costs of screening athletes. Even at UK prices, which are manyfold less than those in the United States, the costs of screening and evaluating just 11,000 athletes came to more than $4 million.
What did these millions buy? The ultimate goal of any pre-participation screening program is to prevent young kids from dying. Yet, in a best-case scenario for sports screening, using both ECG and echo, and using only expert sports cardiologists, six of the eight people who died had normal test results. This degree of false-negative findings is shocking.
It is why I led with the Karl Popper quote. This study teaches us how little we know about the detection of rare heart diseases. This ignorance should give us pause.
If one of the world's leading centers in sports medicine cannot detect disease in almost 75% of those who died, should we continue to force kids and parents to submit to mandatory screening? And if we continue to spend millions doing this, who does it benefit—the tested or the testers?
Perhaps the better answer to prevention of kids dying on the field is more training in cardiopulmonary resuscitation and better access to automated external defibrillators. Surely, based on these findings, screening should be voluntary, and the athletes and parents should be informed of the uncertainties.
We accept the risks of letting adolescents drive vehicles. We know some will die. We do our best to protect them—such as by building safer cars.
Is it silly to say that the risk for sudden death in athletes is something we will have to live with? Why not let kids play, and then provide them with the best possible safety net?
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: John M. Mandrola. Should Mandatory Screening of Young Athletes End? - Medscape - Aug 09, 2018.