Risk and consequences of chemotherapy-induced thrombocytopenia in US clinical practice

Chemotherapy-induced thrombocytopenia (CIT) is a potentially serious complication that can lead to chemotherapy dose delays, dose reductions, or discontinuation, and increases the risk of serious bleeding events. The objectives of this study were to characterize the incidence, clinical consequences, and economic costs of CIT in current US clinical practice. A retrospective cohort design and data from two US private healthcare claims repositories (01/2010-12/2016) were employed. Study population comprised adults who received selected myelosuppressive chemotherapy regimens for solid tumors or non-Hodgkin's lymphoma. CIT was identified based on: diagnosis code for thrombocytopenia or bleeding; procedure code for platelet transfusion or bleeding control; or drug code for thrombopoietin-receptor agonist. Incidence of CIT was evaluated during the chemotherapy course (max. no. cycles = 8), and associated consequences and costs (2016US$) were evaluated during the cycle of the CIT episode. Among 215,508 cancer chemotherapy patients, CIT incidence during the course (mean no. cycles = 4.6) was 9.7% (95% CI: 9.6-9.8), and ranged from 6.1% (5.9-6.3) for regimens containing cyclophosphamide to 13.5% (12.7-14.3) for regimens containing gemcitabine; among all patients, incidence was 2.7% (2.6-2.8) in cycle 1, 2.7% (2.6-2.8) in cycle 2, and 2.9% (2.9-3.0) in cycles thereafter. One-third of CIT episodes were managed in hospital, and for the subset of patients hospitalized with a first-listed diagnosis of CIT, mean length of stay was 4.6 (4.4-5.0) days and mean cost of inpatient care was $36,448 (32,332-41,331). Across cycles with CIT, mean cost of CIT-related care was $2179 (2029-2329), comprising $1024 (881-1167) for inpatient care and $1153 (1119-1187) for outpatient care. In this retrospective evaluation of cancer chemotherapy patients, CIT incidence was high, especially among patients receiving gemcitabine-based regimens, and the costs of CIT-related care were substantial. Accordingly, interventions aimed at identifying and targeting high-risk patients for preventative measures may yield substantial clinical and economic benefits.