Admission Total Leukocyte Count as a Predictor of Mortality in Cardiac Intensive Care Unit Patients

Ryan J Smith; Dhruv Sarma; Mitchell R Padkins; Ognjen Gajic; Patrick R Lawler; Sean Van Diepen; Kianoush B Kashani; Jacob C Jentzer

doi:10.1016/j.jacadv.2023.100757

Admission Total Leukocyte Count as a Predictor of Mortality in Cardiac Intensive Care Unit Patients

JACC Adv. 2023 Dec 8;3(1):100757. doi: 10.1016/j.jacadv.2023.100757. eCollection 2024 Jan.

Authors

Ryan J Smith¹, Dhruv Sarma¹, Mitchell R Padkins², Ognjen Gajic³, Patrick R Lawler^{4

5}, Sean Van Diepen⁶, Kianoush B Kashani^{3

7}, Jacob C Jentzer²

Affiliations

¹ Department of Internal Medicine, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, Minnesota, USA.
² Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
³ Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
⁴ Divisions of Cardiology and Clinical Epidemiology, Jewish General Hospital/McGill University, Montreal, Quebec, Canada.
⁵ Department of Medicine, McGill University Health Center, Montreal, Quebec, Canada.
⁶ Department of Critical Care Medicine and Division of Cardiology, Department of Medicine, University of Alberta Hospital, Edmonton, Alberta.
⁷ Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.

Abstract

Background: Inflammation is a sequela of cardiovascular critical illness and a risk factor for mortality.

Objectives: This study aimed to evaluate the association between white blood cell count (WBC) and mortality in a broad population of patients admitted to the cardiac intensive care unit (CICU).

Methods: This retrospective cohort study included patients admitted to the Mayo Clinic CICU between 2007 and 2018. We analyzed WBC as a continuous variable and then categorized WBC as low (<4.0 × 10³/mL), normal (≥4.0 to <11.0 × 10³/mL), high (≥11.0 to <22.0 × 10³/mL), or very high (≥22.0 × 10³/mL). The association between WBC and in-hospital mortality was evaluated using multivariable logistic regression and random forest models.

Results: We included 11,699 patients with a median age of 69.3 years (37.6% females). Median WBC was 9.6 (IQR: 7.4-12.7). Mortality was higher in the low (10.5%), high (12.0%), and very high (33.3%) WBC groups relative to the normal WBC group (5.3%). A rising WBC was incrementally associated with higher in-hospital mortality after adjustment (AICc adjusted OR: 1.03 [95% CI: 1.02-1.04] per 1 × 10³ increase in WBC). After adjustment, only the high (AICc adjusted OR: 1.37 [95% CI: 1.15-1.64]) and very high (AICc adjusted OR: 1.99 [1.47-2.71]) WBC groups remained associated with increased risk of in-hospital mortality.

Conclusions: Leukocytosis is associated with an increased mortality risk in a diverse cohort of CICU patients. This readily available marker of systemic inflammation may be useful for risk stratification within the increasingly complex CICU patient population.

Keywords: CICU; WBC; inflammation; mortality.