Testing of sickle cell trait for athletes unwise (essay)
This week, members of the National Collegiate Athletic Association’s Division III will vote on a medically controversial and unsubstantiated policy regarding sickle cell trait (SCT) testing for Division III athletes. Based on the current medical literature, the delegates would be wise to vote against the proposal.
The policy stems from a 2009 settlement by the NCAA of a lawsuit involving the death of a Rice University football player. The death was attributed to SCT, and the NCAA began recommending that athletics departments confirm SCT status in all athletes, if it is not already known, during their required medical examinations. While individuals can opt out if they agree to education and sign liability waivers, mandatory SCT education and confirmation of SCT status of athletes began in Division I in 2010, and in Division II in 2011. The current NCAA proposal would extend the policy to Division III starting in 2013.
SCT is a genetic condition involving red blood cells. Unlike sickle cell disease, which can have serious health consequences, SCT individuals do not typically experience any symptoms and may not know that they have SCT. The red blood cells in individuals with sickle cell disease or SCT can become deformed and lead to health problems. This is known as sickling, and is far more common in individuals with sickle cell disease.
Recent reports in the medical literature have suggested that SCT may contribute to death in athletes. The topic remains highly controversial, with some authors suggesting that exertional sickling has killed or led to collapse of many athletes and military trainees. Other authors disagree, and suggest that SCT screening is unnecessary and may be harmful, and that implementing education and universal safety measures would protect all athletes.
In January, 2012 the American Society of Hematology (ASH) issued a statement opposing the NCAA SCT screening policy as a means to reduce exertion-related illness or death. Other expert groups and medical organizations, such as the American Medical Society for Sports Medicine and a Department of Health and Human Services advisory committee, have published papers or statements that recognize but do not endorse mandatory pre-participation SCT testing. The authors of these papers and statements advocate for further research, education of athletes and coaches, and implementation of safety measures rather than screening.
Hematology and sports medicine experts are correct in not endorsing mandatory testing because the pathophysiology of SCT-associated death remains unknown. The well-intentioned pro-SCT testing argument is based on limited information obtained from autopsies and case reports, and may not have fully investigated other potential contributors to the athlete’s demise. The presumption that SCT contributed to the athlete’s death because deformed/sickled cells were found at autopsy may not be accurate. The problem is that the presence of sickled cells in postmortem tissue specimens from a person with SCT does not guarantee pre-mortem sickling. Red blood cells can become deformed in SCT patients when they are deprived of oxygen. Since this is exactly what happens when a person dies, we might expect to see sickled cells in an autopsy of a patient with SCT. As one author wrote: “Sickling seen in postmortem samples is most likely an artifact of death.”
More importantly, good medical policy should rest on a foundation of evidence-based medicine. Unfortunately, well-controlled, hypothesis-driven prospective studies on SCT and exertional collapse are lacking. More research is needed to understand the pathophysiology of death in athletes with SCT, and determine whether screening high-risk populations reduces mortality. It is particularly interesting that two recent papers on SCT, co-authored by the NCAA’s director of health and safety, David Klossner, and published after the 2010 NCAA Division I SCT rule went into effect, have concluded that additional research is needed to understand the value of screening for SCT in athletes.
Epidemiologists have noted that an extremely small number of deaths in a highly prevalent carrier state implies that other genetic or environmental factors play a role. SCT is considered a fairly common condition, yet only a small number of athletes have presumably succumbed from SCT over the past 30-40 years. The reported deaths also have a high predilection for Division I football players. As one study noted, all but 2 of 19 deaths associated with SCT in NCAA athletes since 1973 have been in Division I football players. There were no deaths related to SCT in Division III athletes, including Division III football players.
The proposed testing method has also raised concerns. Due to cost, the NCAA is recommending that schools use a blood test that experts consider to be inferior and less accurate than more expensive methods. The NCAA-proposed test does not have the ability to identify other forms of blood disorders. False negative tests would provide false reassurance, potentially putting athletes at even greater risk. Finally, athlete and military recruit deaths have occurred despite knowledge of sickle cell trait in the individual.
While the NCAA should be praised for its interest in athlete safety, it has misrepresented medical data in its quest to mandate SCT testing for all athletes. For example, in the October 2012 NCAA DIII monthly update the NCAA stated that: “Another study, published in 2012, concluded that student-athletes with sickle cell trait have a relative risk of exertion-related death that is 37 times higher than those without it.” However, the original paper notes that: “All deaths associated with SCT occurred in black Division I football athletes. The risk of exertional death in Division I football players with SCT was 37 times higher than in athletes without SCT.”
That is an important distinction when considering a screening program that would annually affect thousands of athletes. The same NCAA Division III update also stated that “13.6 percent of Division III schools that participated reported removing a student-athlete with sickle cell trait from a competition, practice or workout because they were concerned they may be developing a dangerous condition secondary to their sickle cell trait status.” However, supporting evidence that patient symptoms were due to complications from SCT is not provided, and their condition cannot be attributed to SCT. The NCAA’s assertion that “the knowledge of a student-athlete’s sickle cell trait status can lead to appropriate precautions and interventions” is not supported in the available medical literature and remains controversial.
The cost of an SCT screening program, while secondary to an institution’s interest in protecting its students, must also be considered. The NCAA-published basic solubility test costs between $8.50 and $32.50 per test. The $8.50 test does not include phlebotomy costs, which would add $5 to $10 per test. Some schools do not have easy access to the lab associated with the NCAA pricing and are looking at costs as high as $75 per athlete tested. Administrative costs associated with tracking results and compliance have not been included in the NCAA analysis and could place a significant burden on DIII sports medicine departments, which typically have fewer resources than other NCAA divisions. Most importantly, the cost of an unproven screening program may divert funding away from other important health issues.
Rather than succumb to fear or the NCAA’s institutional momentum, the Division III delegates voting on the SCT screening measure should base their vote on sound scientific principles and recognize that many caring and responsible physicians and medical organizations have opposed screening for SCT. The NCAA has exaggerated existing medical data and is promoting use of an inferior screening test that may lead to false reassurances.
The delegates would be wise to pass a measure that promotes further research on the role of SCT in exertion related collapse and death, emphasizes education of athletes around SCT and other issues that may cause harm, promotes a voluntary testing process that includes a personal discussion between an athlete and their physician, and most importantly, adopts universal safety precautions and measures to enhance the safety of all athletes.
Mark Peluso is medical director and head team physician at Middlebury College. Paul Berkner is the medical director and team physician at Colby College. Both are active in national sports medicine and pediatric groups.