Response to Letter Regarding Article, “Incidence of Sudden Cardiac Death in National Collegiate Athletic Association Athletes”
We thank Dr Angelini and colleagues for their comments regarding our recent article.1 They are concerned about the potential limitations regarding the calculation of sudden cardiac death (SCD) incidence rates in National Collegiate Athletic Association (NCAA) athletes. Incidence is calculated as the number of cases per population in a given time period, and has universally been defined in past studies of athletes as an annual risk, or the number of cases per athlete population that occur in 1 year.23 Taking the average number of cases each year divided by the exact number of athlete participants each year provides an accurate incidence rate (athletes with SCD per year). NCAA athletes will compete, on average, for 4 years, making the total number of individual athletes different than the total number of athlete participation years in this study. However, the risk of SCD is an annual risk and not just during 1 year of the athlete's career.
We agree that SCD in this group of athletes is attributable to silent cardiovascular disease. The overall incidence of 1:43 000 represents a minimum and does not account for any athletes disqualified before competition, any who had sudden cardiac arrest and survived, or who were missed in our data collection. The true incidence of serious cardiovascular events is probably higher.
We included all causes of death in NCAA athletes as a way to emphasize that SCD is an important, potentially preventable cause of death in this cohort. SCD is the leading medical cause of death, with a death rate 9 times higher than deaths related to sickle cell trait, currently an area of preventative legislation for the NCAA. Causality was not commented on because autopsy data were not uniformly available for all cases.
The Memorial Resolutions List did not capture all SCD. A capture-recapture analysis estimated that, in the population studied, there should have been 49 deaths (versus the 45 discovered). Thus, the information from the Memorial Resolutions List identified only 80% of probable cases (39/49), and the media database identified a mere 51% (25/49) of cases. Insurance claims data were not used to create the final NCAA database, but were only compared with it. A mandatory and systematic reporting system clearly would be an improvement.
Despite the limitations in this study, it is the most accurate study to date on the incidence of SCD in a US population of athletes. The information can be used to guide prevention strategies.
Kimberly G. Harmon, MD
Departments of Family Medicine and Orthopaedics
University of Washington
Irfan M. Asif, MD
University of Washington Medical Center
David Klossner, ATC, PhD
National Collegiate Athletic Association
Jonathan A. Drezner, MD
Department of Family Medicine
University of Washington
- © 2011 American Heart Association, Inc.
- Harmon KG,
- Asif IM,
- Klossner D,
- Drezner JA
- Maron BJ,
- Doerer JJ,
- Haas TS,
- Tierney DM,
- Mueller FO