Reliability of leukostasis grading score to identify patients with high-risk hyperleukocytosis

Hyperleukocytosis, white blood cell (WBC) count exceeding 50 to 100 x 10(9)/L, mostly occurs in acute leukemias, is a clear adverse prognostic factor for overall survival, and is associated with increased early mortality. Novotny et al. [1] developed a score to grade the probability of leukostasis in patients with hyperleukocytic leukemia. It is based on the simple clinical evaluation of overall severity of symptoms, the presence of pulmonary or neurologic symptoms with assignment of a score. We retrospectively applied this leukostasis grading score (LGS) to patients admitted to our institution from 1995 to 2008 with a newly diagnosed acute leukemia presenting with hyperleukocytosis to identify patients at high risk of early death. Thirty-three patients presented hyperleukocytosis. Six patients died within 1 week. More than 75% of patients with hyperleukocytosis were assigned a LGS >= 2 and almost 50% had an LGS of 3. Higher LGS was observed in patients with myeloid phenotype. LGS, age, bilirubin, creatinine, and lactate dehydrogenase (LDH) were the factors statistically associated with the occurrence of early death. Multivariate analysis confirms only LGS 3 as predictive of early death. The score is simple and is able to identify patients at higher risk of early death immediately requiring more aggressive treatment.