Objective: We sought to determine the relationship between the lowest lymphocyte count (lymphocytemin) obtained within the first 96 h of symptoms onset and the risk of postdischarge recurrent spontaneous myocardial infarction (re-MI) in patients admitted with ST-segment elevation MI (STEMI).
Methods: We analyzed 549 consecutive patients admitted with STEMI from a single academic hospital. Lymphocyte counts were determined at admission and routinely during the first 96 h. Lymphocytemin was selected as the main exposure. Patients with inflammatory or infectious diseases, in-hospital death, or reinfarction were excluded from the analysis (final sample=426 patients). Lymphocytemin was divided into quartiles (Q) and their association with re-MI was assessed by competing risk analysis. Postdischarge death and coronary revascularization were considered competing events.
Results: During a median follow-up of 36 months, 53 re-MI (12.4%) were registered. The re-MI crude rate was significantly higher in patients in the lowest lymphocytemin quartile (Q1≤1045 cells/ml) compared with Q2–Q4: 22.4, 9.4, 8.4, 9.4%, respectively; P=0.005. In a multivariate setting, Q1 was also associated with a significant increased risk of re-MI compared with Q2–Q4 (hazard ratio: 2.04, 95% confidence interval: 1.11–3.76; P=0.021).
Conclusion: Low lymphocyte count obtained within the first 96 h of a STEMI predicts the risk of re-MI.