Marathon running as a cause of troponin elevation: a systematic review and meta-analysis.

BACKGROUND: Cardiac troponin (cTn) has high sensitivity and specificity for myocardial injury in acute coronary syndrome. Our objective was to review the published literature regarding the incidence of cTn elevations in marathon runners.
METHODS: Systematic review and meta-analysis of observational studies published before September 2009. We included studies of patients who had completed a marathon and had serum cTn levels within 24 hours. The primary outcome was the odds ratio for conversion of a normal pre-marathon cTn to an elevated post-marathon cTn. Secondary outcomes included the pooled prevalence of cTn elevation and comparison of the odds ratio for post-marathon elevation of cTnI versus cTnT.
RESULTS: Sixteen studies of 939 participants met criteria for inclusion. The mean age was 39 ± 4 years and patients were 74 ± 14% male. There were 6 pre-marathon cTn elevations and 579 post-race elevations. The pooled odds ratio for converting from a normal pre-race to an elevated post-race cTn was 51.84 (95% CI 16-168, I² = 66%, P < 0.001). The pooled incidence of a post-marathon cTn elevation was 51% (95% CI 33-69, I² = 98%, P < 0.001) of all runners. For the primary outcome there was no significant publication bias. Age and gender were not associated, but publication date and assay sensitivity was associated with cTn elevation. cTnI was less commonly elevated versus cTnT.
CONCLUSIONS: The available data demonstrate that cTn levels are frequently elevated after a marathon with unclear cardiovascular significance. This elevation of cTn appears to be consistent among a diverse patient population. ©2010, Wiley Periodicals, Inc.