Rotation of the leukocyte count to recurrent cardiac events in stable patients after acute myocardial infarction

Increasing evidence implicates inflammation as a risk factor for coronary a rtery disease. We determined whether an elevated leukocyte count is associa ted with an increased risk of death or reinfarction in stable patients with a past acute myocardial infarction (AMI). The current analysis is a substu dy of the Multicenter Diltiazem Postinfarction Trial, which investigated th e effect of diltiazem on mortality and reinfarction in 2,466 patients hospi talized for AMI. We included 1,294 patients in whom a leukocyte count was o btained 6 months after the index AMI. The composite end point of reinfarcti on or death was used as the primary end point of the study and reinfarction or cardiac death was used as a secondary end point. The study population w as divided into 4 quartiles (Q1, Q2, Q3, and Q4) based on the leukocyte cou nt. During a mean follow-up period of 25 months, 163 patients reached the p rimary end point: 8.7%, 10.9%, 14.0%, and 16.7%, in Q1, Q2, Q3, and, Q4 res pectively (p = 0.01). After adjusting for potential covariates, Cox proport ional-hazards analysis revealed that an increased leukocyte count was assoc iated with an increased risk of both the primary end point (hazard ratio/1 quartile increase in leukocyte count, 1.26; p = 0.003; 95% confidence inter val 1.08 to 1.47) and secondary end point (hazard ratio, 1.18/1-quartile in crease; p = 0.05; 95% confidence interval 1.00 to 1.40). In conclusion, an increased leukocyte count measured in the stable post-AMI period is associa ted with an increased risk of cardiac events. These findings indicate that the leukocyte count may be another marker of an atherosclerotic inflammator y process that contributes to cardiac events in postinfarction patients. (C ) 2001 by Excerpta Medica, Inc.