Triggers of Hospitalization for Venous Thromboembolism
Background—The rate of hospitalization for venous thromboembolism (VTE) is increasing in the United States. While predictors of hospital-acquired VTE are well-known, triggers of VTE prior to hospitalization are not as clearly defined. The objective of this study was to evaluate triggers of hospitalization for VTE.
Methods and Results—A case-crossover study was conducted. Subjects were participants in the Health and Retirement Study, a nationally-representative sample of older Americans. Data were linked to Medicare files for hospital and nursing home stays, emergency department visits, outpatient visits including physician visits, and home health visits from years 1991-2007 (n=16,781). The outcome was hospitalization for venous thromboembolism (n=399). Exposures during the 90-day period prior to hospitalization for VTE were compared to exposures occurring in 4 comparison periods. Infection was the most common trigger of hospitalization for VTE, occurring in 52.4% of the risk periods prior to hospitalization. The adjusted incidence rate ratios (IRR; 95% CI) were 2.90 (2.13, 3.94) for all infection, 2.63 (1.90, 3.63) for infection without a prior hospital or skilled nursing facility stay, and 6.92 (4.46, 10.72) for infection with a prior hospital or skilled nursing facility stay. Erythropoiesis-stimulating agents and blood transfusion were also associated with VTE hospitalization (IRR=9.33, 95% CI: 1.19, 73.42; IRR=2.57, 95% CI: 1.17, 5.64; respectively). Other predictors included major surgeries, fractures (IRR=2.81), immobility (IRR=4.23) and chemotherapy (IRR=5.70). These predictors, combined, accounted for a large proportion (69.7%) of exposures prior to VTE hospitalization as opposed to 35.3% in the comparison periods.
Conclusions—Risk prediction algorithms for VTE should be reevaluated to include infection, erythropoiesis-stimulating agents and blood transfusion.
- Received December 2, 2011.
- Accepted February 29, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited