Screening for SCD-linked conditions An effective screening programme is a useful tool for identifying health concerns in a population and is therefore part of the remit of a benevolent society. There is evidence that a well-constructed SCD screening programme can be valuable in identifying those at risk.1,4 Screening can provide information to athletes, enabling them to make informed decisions regarding their future sporting career. For example, those with an SCD-linked condition can be informed that vigorous exercise creates a 2.5-fold increased risk of SCD with 90% of events occurring during or just after exercise.5 Despite the utility of SCD screening and acknowledging that no screening programmes can be expected to be 100% robust, there are some features about SCD screening that are particularly problematic. The composition of a screening programme itself is contentious. SCD screening is an attempt to detect a cluster of conditions with a common potential outcome, rather than one single condition. Not all of the conditions are equally detectable with one standard screening protocol, and this is compounded by the fact that the prevalence of each of the SCD-linked conditions may vary across ethnic groups.6 The European Society of Cardiology recommends that an ECG should be a routine screening practice, whereas the American Heart Association believes ECG should be reserved for athletes with positive findings on history and examination. Good evidence suggests that the history and examination approach is ineffective for identifying those at risk of SCD.4 Eighty percent of athletes with SCD-linked conditions are asymptomatic, and the addition of clinical examination often adds little. In one reported case series of SCD screening, only one athlete of the 115 was correctly identified using history and examination screening.7 Addition of routine ECG increases the sensitivity of the screening process4 and is the investigation of choice for Wolfe–parkinson–White syndrome and the ion channelopathies.8 It is also highly effective in the detection of hypertrophic and arrythmogenic right ventricular cardiomyopathies (HCM and ARVC). Follow-up studies have shown that ECG has a sensitivity of 95% and a negative predictive value as high as 99.98% for HCM,9 80% of cases of ARVC.8 while it is also reasonable to assume that ECG will detect However, an ECG is not effective in identifying congenital coronary artery anomalies and premature coronary artery atherosclerosis, which may account for approximately 20% of the causes of SCD. Therefore, while screening with ECG can effectively identify some SCD-linked conditions, others may not be. The next problem relates to the ability to predict the risk of death for a particular individual. Death is not inevitable for those diagnosed with a SCD-linked condition, nor will abstaining from competitive sport ensure survival. The prevalence of SCD-linked conditions is significantly higher than the incidence of SCD. The best estimate of the rate of SCD in the USA gives a figure of 1 death per 45 000 athletes per year.10 While there are some justifiable concerns that SCD risk remains underestimated, particularly in certain demographics, there is still a significant discrepancy between this figure and what appears to be the prevalence of potentially lethal cardiovascular condition in young athletes. Screening programmes have consistently shown this prevalence to be between 1 in 500 and 1 in 150 athletes.11 This suggests that in a cohort of 45 000 athletes, between 90 and 300 will have a potentially lethal condition and one will die each year. So, if an athlete has an SCD-linked condition, he/she has between a 0.3% and 1% chance of dying each year that he/she participates in competitive sport while younger than 35 years. Therefore, mandatory exclusion of all at-risk athletes would exclude many who will never go on to suffer an SCD. Despite the problems identified, the authors consider that effective screening is a useful tool and further improvements in screening will be helpful to provide information to individuals. Although mandatory exclusion based on the findings of current screening methods is problematic in the ways presented, our argument is not solely based on the limitations of the scientific data, but is concerned with the infringement of personal liberty. Even if a screening programme existed that could more accurately predict the risk associated with SCD-linked conditions, mandatory exclusion remains unacceptable. Limiting choices of others Forced interference in the lives of competent individuals is generally considered to be unacceptable.12,13 This idea is encapsulated in Mill’s ‘harm principle’, which acknowledges a competent individual as the best judge of his/her own interests, where those interests do not infringe upon or cause harm to others.12 This principle embraces the idea that respecting the individuals’ voluntary judgement and decisions about their life, based on their values, are important for human dignity and self-worth, and therefore people should make their own choices. When others interfere in our lives it is patronising and overbearing because it appears that they know better than we do what is best for us and what shape our lives should take.13 Such interference nummer 2 | juni 2012 | Sport & Geneeskunde 17 Pagina 16
Pagina 18Heeft u een clubmagazine, page flip of online studiegidsen? Gebruik Online Touch: jaarverslag digitaal maken.
Sport & Geneeskunde nummer 2 | Juni 2012 Lees publicatie 14Home