Are myocardial infarction and venous thromboembolism associated? Population-based case-control and cohort studies

- VTE and MI historically have been considered as two separate disease entities.
- Studies suggesting VTE and MI are associated reached conflicting conclusions.
- We found that MI was not a VTE risk factor, and VTE was not a predictor of MI.
- We had 90% power to detect an association of MI with VTE at OR = 2.3, and VTE as a predictor of MI at HR = 1.8.
- It is possible that we missed significant associations of smaller magnitude.

IntroductionBecause the association of myocardial infarction (MI) and venous thromboembolism (VTE) is uncertain, we tested MI as a VTE risk factor and VTE as a predictor of MI.Materials and MethodsUsing Rochester Epidemiology Project resources, we identified all Olmsted County, MN residents with objectively-diagnosed incident VTE over the 13-year period, 1988-2000 (n = 1311), one to two resident controls per VTE case (n = 1511), and all residents with incident MI over the 31-year period, 1979-2010. For VTE cases and controls, we reviewed their complete medical records in the community for VTE and MI risk factors. Using conditional logistic regression we tested MI as a potential VTE risk factor, both unadjusted and after adjusting for VTE risk factors. We also followed VTE cases and controls without prior MI forward in time for incident MI through 12/31/2010, and using Cox proportional hazards modeling, tested VTE as a predictor of MI, both unadjusted and after adjusting for MI risk factors.ResultsThe number (%) of MI prior to VTE among cases and controls were 75 (5.7) and 51 (3.4), respectively, and the number (%) of MI after VTE among cases and controls were 58 (4.4) and 77 (5.1), respectively. In univariate analyses, MI was significantly associated with VTE but not after adjusting for VTE risk factors. In both univariate and multivariate analyses, VTE (overall or idiopathic) was not a predictor of MI.ConclusionsMI is not an independent risk factor for VTE, and VTE is not a predictor of MI.