Increasing risk for venous thromboembolism among hospitalized cancer patients

Abstract

9009 Background: Venous thromboembolism (VTE) contributes to morbidity and mortality in cancer patients and is a frequent complication of anti-cancer therapy. We examined the frequency, risk factors and trends associated with VTE among hospitalized US cancer patients. Methods: We conducted a retrospective cohort study using the discharge database of the University Health System Consortium. This included all 1,824,316 hospitalizations of cancer patients between 1995 and 2003 at 133 United States medical centers. To avoid overestimation, only a single randomly chosen hospitalization was included for patients with multiple admissions. Results: Among 1,015,598 individual cancer patients, 34,357 (3.4%) were diagnosed with deep venous thrombosis and 11,515 with pulmonary embolism (PE) (1.1%) for an overall VTE rate of 4.1%. Subgroups of cancer patients with highest rates included Black ethnicity (5.1% per hospitalization) and those on chemotherapy (4.9%). Sites of cancer with the highest rates of VTE included pancreas (8.2%), kidney (5.7%), ovary (5.6%), lung (5.1%) and stomach (4.9%). Amongst hematologic malignancies, myeloma (5%), non-Hodgkin’s lymphoma (4.8%) and Hodgkin’s disease (4.6%) had the highest rates of VTE. The rate of VTE rose from 3.6% per hospitalization in 1995–96 to 4.6% in 2002–03, an increase of 28%, including a near-doubling of PE rates from 0.8% to 1.5% (P<0.0001). Among patients receiving chemotherapy, rates of VTE rose from 3.9% per hospitalization to 5.7%, an increase of 47% (P<0.0001). In contrast, patients undergoing surgery for breast, head and neck, pancreatic or spinal cancers, experienced no significant change in the rate of VTE. Use of diagnostic procedures for VTE also did not increase over the study period. Conclusions: The rate of VTE, including PE, among hospitalized cancer patients has increased significantly in recent years. Black patients, those on chemotherapy and those with certain types of cancer are disproportionately at increased risk. The rise in VTE does not appear to be attributable to an increased utilization of diagnostic procedures. Further efforts to increase thromboprophylaxis compliance during hospitalization are needed. No significant financial relationships to disclose.