Michel Grivaux

Cancer patients receiving chemotherapy are at increased risk of venous thromboembolism (VTE). The presence of cancer and anticoagulant use are risk factors for bleeding, yet data on bleeding risk are limited in these patients. This analysis evaluated the risk of major bleeding in cancer patients receiving chemotherapy using a US claims database. This retrospective cohort study used the MarketScan^® databases, a nationwide database containing data from about 100 payers and covering > 30 million patients annually. Adult cancer patients receiving chemotherapy within 6 months of cancer diagnosis between January 2004 and December 2010 were included. Cancers of interest were: lung, colon/rectum, pancreas, bladder, stomach, and ovary. The index date was the first date of chemotherapy. Patients were followed until the earliest of: 1) first diagnosis of major bleeding; 2) termination of enrolment in the health plan; 3) end of study. The primary outcome was the first occurrence of major bleeding, based on selected ICD-9-CM/CPT codes, following chemotherapy initiation. Of 74,575 patients identified, exclusion of those with prior history of bleeding at baseline (∼5%) resulted in 70,822 patients included in the analysis. Mean age was 62 years, 37% were ≥ 65 years, and 52% were male. Average time of follow up and chemotherapy were 14.3 and 8.6 months, respectively; 6% had a history of VTE within 6 months prior to the index date. Major bleeding occurred in 5.8% of patients and the incidence rate for all cancers combined was 4.9 per 100 person-year (PY) and 10.5, 9.3, 6.2, 4.3, 3.6, and 3.3/100 PY for pancreatic, stomach, lung, bladder, colon/rectum, and ovarian cancer, respectively. Approximately 14% of patients (N = 10,456) developed VTE after chemotherapy initiation (> half in the first 3 months of chemotherapy treatment). Of these, 7.8% experienced major bleeding with incidence rates ranging from 5.9-17.7/100 PY after VTE. Major bleeding incidence in cancer patients receiving chemotherapy varies by cancer type with the highest rates in patients with upper gastrointestinal cancer. Compared to the overall cohort, major bleeding risk was higher in cancer patients who developed VTE.