Relative Lymphocytopenia and Outcome of Myocardial Infarction.
A Population-Based Study in Olmsted County, MN
Background: There is evidence for the role of inflammation in the pathogenesis of coronary disease. Relative lymphocytopenia was reported for the diagnosis of myocardial infarction (MI), but little is known about its prognostic value. This study was undertaken to test the hypothesis that relative lymphocytopenia was associated with cardiac events (defined as recurrent MI, congestive heart failure or cardiac death) after MI among Olmsted County residents. Methods: MIs were validated using standard epidemiological criteria using enzymes, chest pain and Minnesota coding of the ECG. The entire community medical record, available via the Rochester Epidemiology Project, was reviewed to determine incident status and ascertain outcomes. Relative lymphocytopenia was defined as percent lymphocytes<20, 3%. Results: Between 1979 and 1994, an incidence cohort of 1653 validated MIs (mean age 67 ± 14, 43% women) was assembled. At the time of index MI, relative lymphocytopenia was present in 51% of the cases. After a mean follow-up of 6.9 ± 5.4 years, 471 pts had experienced recurrent MIs, 849 pts CHF and 602 cardiac deaths occurred. The 5-year event-free survival was 35% for cases with relative lymphocytopenia vs 52% for those without(p<0.001). After adjustment for age and current smoking, relative lymphocytopenia was associated with a 21% increase in the risk of cardiac event (RR 1.21, 95% CI 1.1-1.4; p=0.003). Conclusion: Relative lymphocytopenia is associated with cardiac events after incident MI. These data support the role of inflammation in the outcome of coronary disease.