Nucleated Red Blood Cells as Predictors of All-Cause Mortality in Cardiac Intensive Care Unit Patients: A Prospective Cohort Study

BACKGROUND The presence of nucleated red blood cells (NRBCs) in the peripheral blood of critically ill patients is associated with a poorer prognosis, though data on cardiovascular critical care patients is lacking. The aim of the present study was to assess the role of NRBCs as a predictor of intensive care unit (ICU) and in hospital all-cause mortality among cardiologic patients. METHODS NRBCs were measured daily in consecutive cardiac ICU patients, including individuals with both coronary and non-coronary acute cardiac care. We excluded patients younger than 18 years, with cancer or hematological disease, on glucocorticoid therapy, those that were readmitted after hospital discharge and patients who died in the first 24 hours after admission. We performed a multiple logistic analysis to identify independent predictors of mortality. RESULTS We included 152 patients (60.6 ± 16.8 years, 51.8% female, median ICU stay of 7 [4-11] days). The prevalence of NRBCs was 54.6% (83/152). The presence of NRBC was associated with a higher ICU mortality (49.4% vs 21.7%, P<0.001) as well as in-hospital mortality (61.4% vs 33.3%, p = 0.001). NRBC were equally associated with mortality among coronary disease (64.71% vs 32.5% [OR 3.80; 95%CI: 1.45-10.0; p = 0.007]) and non-coronary disease patients (61.45% vs 33.3% [OR 3.19; 95%CI: 1.63-6.21; p<0.001]). In a multivariable model, the inclusion of NRBC to the APACHE II score resulted in a significant improvement in the discrimination (p = 0.01). CONCLUSIONS NRBC are predictors of all-cause in-hospital mortality in patients admitted to a cardiac ICU. This predictive value is independent and complementary to the well validated APACHE II score.