Idiosyncratic Drug-Induced Severe Neutropenia and Agranulocytosis in Elderly Patients (≥75 years): A Monocentric Cohort Study of 61 Cases

BACKGROUND: Little data is currently available in the literature on neutropenia and agranulocytosis in the elderly, and, to our knowledge, idiosyncratic drug-induced agranulocytosis is particularly poorly covered, or not at all. OBJECTIVE: We herein describe the clinical picture and outcome of patients aged ≥75 years with established idiosyncratic drug-induced agranulocytosis. PATIENTS AND METHODS: Data from 61 patients over 75 years old with idiosyncratic drug-induced agranulocytosis were retrospectively reviewed. All cases were extracted from a cohort study on agranulocytosis (n = 203) in the Strasbourg University Hospitals (Strasbourg, France), a referral center. RESULTS: The mean age was 84.9 years (range 75–95), the gender ratio (F/M) was 2.4. Underlying diseases were present in 74 %. The most frequent causative drugs were antibiotics (43.8 %), antithyroid drugs (15.8 %), neuroleptic and anti-epileptic agents (12.3 %), and antiaggregant platelet agents (10.5 %). The primary clinical features during hospitalization included isolated fever (27.6 %), septicemia or septic shock (24.1 %), and pneumonia (20.7 %). The mean neutrophil count at nadir was 0.15 × 10(9)/L (range 0–0.4). All febrile patients were treated with broad-spectrum antibiotics and 36 with hematopoietic growth factors. Outcome was favorable in 85.3 % of patients; nine patients died. Two elderly patients (3.3 %) died of uncontrolled septic shock relating to the depth of the neutropenia. Comparison of mortality between <75- and ≥75-year-old patients revealed a statistical difference: 4.2 % versus 14.8 % (p = 0.023). CONCLUSIONS: Our study demonstrates that 30 % of idiosyncratic drug-induced agranulocytosis concerned elderly patients. Antibiotic, antithyroid, neuroleptic, anti-epileptic, and antiaggregant platelet agents are the primary causative drug classes. Idiosyncratic drug-induced agranulocytosis is typically serious in this frail population of elderly patients, with at least 50 % suffering from severe sepsis and with a mortality rate of approximately 15 %. Modern management of agranulocytosis may reduce the infection-related mortality (3.3 %).