Incidence of Sudden Cardiac Arrest and Death in Young Athletes and Military Members: A Systematic Review and Meta-Analysis.

OBJECTIVE: To evaluate the quality of the evidence on the incidence of sudden cardiac arrest (SCA) and sudden cardiac death (SCD) in athletes and military members and estimate the annual incidence of SCA and SCD. DATA SOURCES: We searched MEDLINE, Embase, Cochrane CENTRAL, Web of Science, BIOSIS, Scopus, SPORTDiscus, PEDro, and ClinicalTrials.gov from inception to dates between February 21 and July 29, 2019. STUDY SELECTION: Studies in which the incidence of SCA, SCD, or both in athletes or military members aged <40 years was reported were eligible for inclusion. We identified 40 studies for inclusion. DATA EXTRACTION: Risk of bias (ROB) was assessed using a validated, customized tool for prevalence studies. Twelve had a low ROB, while the remaining 28 had a moderate or high ROB. Data were extracted for narrative review and meta-analysis. DATA SYNTHESIS: Random-effects meta-analysis was performed in studies judged to have a low ROB in 2 categories: (1) 5 studies of regional- or national-level data, including athletes at all levels and both sexes, demonstrated 130 SCD events with a total of 11 272 560 athlete-years, showing a cumulative incidence rate of 0.98 (95% CI = 0.62, 1.53) per 100 000 athlete-years and high heterogeneity (I2 = 78%) and (2) 3 studies of competitive athletes aged 14 to 25 years were combined for a total of 183 events and 17 798 758 athlete-years, showing an incidence rate of 1.91 (95% CI = 0.71, 5.14) per 100 000 athlete-years and high heterogeneity (I2 = 97%). The remaining low-ROB studies involved military members and were not synthesized. CONCLUSIONS: The worldwide incidence of SCD is rare. Low-ROB studies indicated the incidence was <2 per 100 000 athlete-years. Overall, the quality of the available evidence was low, but high-quality individual studies inform the question of incidence levels. PROSPERO REGISTRATION: CRD42019125560.

Screening Electrocardiogram in Young Athletes and Military Members: A Systematic Review and Meta-Analysis.

OBJECTIVE: To determine the effect of electrocardiogram (ECG) screening on the prevention of sudden cardiac arrest and death in young athletes and military members. DATA SOURCES: MEDLINE, Embase, CENTRAL, Web of Science, BIOSIS, Scopus, SPORTDiscus, PEDro, and ClinicalTrials.gov were searched from inception to dates between February 21 and July 29, 2019. STUDY SELECTION: Randomized and nonrandomized controlled trials in which preparticipation examination including ECG was the primary intervention used to screen athletes or military members aged ≤40 years. Acceptable control groups were those receiving no screening, usual care, or preparticipation examination without ECG. Three published studies and 1 conference abstract were identified for inclusion. DATA EXTRACTION: In all 4 studies, risk of bias was assessed using the Cochrane risk-of-bias tool and was found to be generally high. Two studies had data extracted for random effects meta-analysis, and the remaining study and conference abstract were included in the narrative review. The overall quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation approach. DATA SYNTHESIS: We included 4 nonrandomized studies (11 689 172 participants), of which all had a high risk of bias. Pooled data from 2 studies (n = 3 869 274; very low-quality evidence) showed an inconclusive 42% relative decrease in risk of sudden cardiac death (relative risk = 0.58; 95% CI = 0.23, 1.45), equating to an absolute risk reduction of 0.0016%. The findings were consistent with a potential 77% relative decreased risk to a 45% relative increased risk in participants screened using ECG. Heterogeneity was found to be high, as measured using I2 statistic (71%). Data from the remaining study and abstract were similarly inconclusive. CONCLUSIONS: Existing evidence for the effect of ECG screening is inconclusive and of very low quality. In our meta-analysis, we observed that screening ECG may result in a considerable benefit or harm to participants. Higher-quality studies are needed to reduce this uncertainty.