Objective: We sought to determine the relationship between the lowest lymphocyte count (lymphocyte(min))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. Lymphocyte(min) 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). Lymphocyte(min) 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 lymphocyte(min) quartile (Q1r1045 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.