Comparison of United States and Italian Experiences With Sudden Cardiac Deaths in Young Competitive Athletes: Are the Athletic Populations Comparable?

In a recent study, Maron et al compared the incidence of sudden cardiovascular death between high school and college athletes from Minnesota, where no preparticipation electrocardiographic screening is practiced, and young competitive athletes from the Veneto region of Italy, who underwent systematic electrocardiographic screening for >25 years, with an ensuing 90% mortality decrease from 1982 to 2004. During the time period from 1993 to 2004, there were 12 deaths in the Veneto region and 11 in Minnesota (0.87 vs 0.93 per 100,000 athletes annually, respectively, p = 0.88). The investigators concluded that because sudden death rates in these demographically similar regions did not differ significantly in recent years, sudden cardiac death in athletes is a phenomenon with a low event rate that is unlikely to be influenced by preparticipation cardiovascular evaluation.

We believe that the relative mortality rates of young athletes from the United States and Italy must be evaluated by comparing populations (other than from demographically similar regions) matched for gender and age, because the risk for sudden cardiac death in athletes is greater in male athletes and increases significantly with age. The incidence of sudden cardiac death has been estimated to be 5 to 10 times higher for male than for female athletes. Male college athletes (age range 18 to 22 years) had twice the estimated death rate of their high school (age range 12 to 18 years) counterparts (1.45 vs 0.66 per 100,000 athletes per year).

The United States mortality rates reported by Maron et al refer mostly to high school and college participants (age range 12 to 22 years), including approximately 65% male athletes. The Italian athletic population differs substantially because of the inclusion of more male athletes (approximately 80%) and, most important, because of a broader age range (12 to 35 years), including a significant group of older competitors. Noteworthy is that the mean age of Italian athletes who died suddenly was 23 ± 2 years, with 60% of the victims aged >22 years, whereas the mean age of sudden death victims in the Maron et al’s study was 17 ± 4 years (p <0.01). This age-group discrepancy explains the different prevalence between the 2 series of atherosclerotic coronary artery disease, a recognized increasing cause of sudden death in young adults aged >20 years, which was absent in the Minnesota series and was reported only from the Veneto region (8 of 55 sudden death victims [15%]). In this regard, a significantly higher incidence of sudden cardiac death was found in the young adult population (aged 20 to 40 years) of residents from Olmsted County, Minnesota. From 1960 to 1989, there were 40 cases of sudden cardiac death, which produced an overall cohort incidence rate of about 4.5 per 100,000 person-years. Although this study did not report the relative proportions of athletes and nonathletes among sudden death victims, it clearly demonstrates that in the same geographic area of Maron et al’s study, the incidence of sudden cardiac death in young adults aged >20 years increases exponentially to an extent comparable to that observed in the Veneto region during the pre-screening era. Most important, these data on mortality rates were very accurate because of the reliability of the numerator—autopsy examination is compulsory for every case of sudden death occurring in Olmsted County, and all autopsy examinations were actually performed in the pathology department of the Mayo Clinic—and the denominator, based on census data of the Olmsted County population. The design of this study was very similar to the Italian study, which since 1979 has relied on systematic investigation and the collection of juvenile sudden deaths occurring in the Veneto region, with morphologic examination of all hearts performed by the same team of experienced cardiovascular pathologists according to a standard protocol. Although the Italian data were systematically gathered according to a prospective study design, the United States sudden cardiac death rates reported by Maron et al were based mostly on a retrospective analysis of data provided by different sources, such as the Minnesota State High School League, news media information services, Web-based search engines, the LexisNexis archival information database, and the like. Reasonable concerns exist regarding the reliability of these sources of information to estimate athletes’ sudden cardiac death rate, because of their inherent limitations in data collection, unavoidably resulting in an underestimation of mortality. Furthermore, the accuracy of the determination of the incidence of sudden cardiac death in United States athletes is questionable because denominator data did not reflect the real number of active athletes in each given year but the total participation figures divided by an estimate of the average number of sports in which each high school and college athlete participated. Surprisingly, the estimate of the conversion factor (approximately 2.2) was merely based on discussions with representatives of national athletic organizations.

We believe that it is time to establish a prospective registry aimed at conclusively determining the precise incidence of sudden death in young athletes worldwide. In the meantime, however, it would be more prudent to refrain from dismissing sudden cardiac death during sports as a negligible risk, while criticizing preparticipation screening dangerously ignores its lifesaving application. Although the effect of an overestimation of mortality rates would be to spend money for unnecessary screening programs, the social, ethical, and medical costs of an underestimation of sudden death may be immeasurably greater because they may lead to the unreasonable loss of young lives.

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Dec 23, 2016 | Posted by in CARDIOLOGY | Comments Off on Comparison of United States and Italian Experiences With Sudden Cardiac Deaths in Young Competitive Athletes: Are the Athletic Populations Comparable?

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