Hospitalisation for venous thromboembolism in cancer patients and the general population: a population-based cohort study in Denmark, 1997-2006

BACKGROUND: Venous thromboembolism (VTE) frequently complicates cancer. Data on tumour-specific VTE predictors are limited, but may inform strategies to prevent thrombosis. METHODS: We computed incidence rates (IRs) with 95% confidence intervals (CIs) for VTE hospitalisation in a cohort of cancer patients (n = 57 591) and in a comparison general-population cohort (n = 287 476) in Denmark. The subjects entered the study in 1997-2005, and the follow-up continued through 2006. Using Cox proportional-hazards regression, we estimated relative risks (RRs) for VTE predictors, while adjusting for comorbidity. RESULTS: Throughout the follow-up, VTE IR was higher among the cancer patients (IR = 8.0, 95% CI = 7.6-8.5) than the general population (IR = 4.7, 95% CI = 4.3-5.1), particularly in the first year after cancer diagnosis (IR = 15.0, 95% CI = 13.8-16.2, vs IR = 8.6, 95% CI = 7.6-9.9). Incidence rates of VTE were highest in patients with pancreas (IR = 40.9, 95% CI = 29.5-56.7), brain (IR = 17.7, 95% CI = 11.3-27.8) or liver (IR = 20.4, 95% CI = 9.2-45.3) tumours, multiple myeloma (IR = 22.6, 95% CI = 15.4-33.2) and among patients with advanced-stage cancers (IR = 27.7, 95% CI = 24.0-32.0) or those who received chemotherapy or no/symptomatic treatment. The adjusted RR (aRR) for VTE was highest among patients with pancreas (aRR = 16.3, 95% CI = 8.1-32.6) or brain cancer (aRR = 19.8 95% CI = 7.1-55.2), multiple myeloma (aRR = 46.1, 95% CI = 13.1-162.0) and among patients receiving chemotherapy, either alone (aRR = 18.5, 95% CI = 11.9-28.7) or in combination treatments (aRR = 16.2, 95% CI = 12.0-21.7). CONCLUSIONS: Risk of VTE is higher among cancer patients than in the general population. Predictors of VTE include recency of cancer diagnosis, cancer site, stage and the type of cancer-directed treatment. British Journal of Cancer (2010) 103, 947-953. doi:10.1038/sj.bjc.6605883 www.bjcancer.com Published online 14 September 2010 (C) 2010 Cancer Research UK