Prognostic significance of marked leukocytosis in hospitalized patients.

STUDY OBJECTIVE: To identify the prognostic significance of marked neutrophilic leukocytosis (MNL), defined as white blood cell (WBC) count of greater than or equal to 25,000/microL and greater than or equal to 80% mature neutrophils by differential count, in hospitalized patients.

DESIGN: A central laboratory computer identified all consecutive patients with MNL in a one-month period. After exclusion of outpatients, neonates, and patients with hematologic malignancies or incomplete records, the remaining patients were studied and followed until discharge or death.

SETTING: Inpatient services of a 988-bed tertiary care teaching hospital.

PATIENTS: 72 inpatients with MNL.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Associated conditions and hospital mortality were recorded. Potentially confounding or contributing variables, including age, sex, intensive care unit stay, infection, acidosis, uremia, malignancy, hemorrhage, surgery or invasive procedure, peak WBC count, and duration of MNL, were examined by multivariate analysis with mortality as the outcome variable. Overall hospital mortality was 29% in study patients. A higher peak WBC count (p = 0.0046), increasing age (p = 0.0058), MNL duration of greater than one day (p = 0.025), and lack of associated invasive procedures (p = 0.04) were jointly significant in the prediction of mortality in MNL patients.

CONCLUSIONS: The results confirm the impression of poor outcome associated with MNL and validate the use of MNL data in indices of severity of illness and as a prognostic marker for hospitalized patients regardless of underlying disease.