Venous thromboembolism and risk of cancer in patients with diabetes mellitus

Abstract

Aim Venous thromboembolism (VTE) has long been regarded as a marker of underlying malignancy in the general population. Patients with diabetes mellitus are at increased risk of developing VTE, but it is unclear whether VTE in diabetes patients is also a harbinger of occult cancer. Methods From Danish medical health databases, we identified all diabetes patients (N = 8783) with a first-time diagnosis of VTE during 1978-2011. We followed the patients until a first-time diagnosis of cancer, emigration, death, or study end, whichever came first. We calculated one-year absolute cancer risk and overall and site-specific standardized incidence ratios (SIRs) for cancer based on national cancer incidence. Results During the total study period 878 cancers were observed. The one-year absolute cancer risk was 4.1% and the corresponding SIR was 3.28 (95% confidence interval [CI]: 2.94-3.64). The highest SIRs were observed for cancers of the gallbladder and biliary tract (SIR 13.59; 6.77-24.31), the pancreas (SIR 10.16; 6.85-14.50), the ovary (SIR 9.85; 5.63-16.00), and the liver (SIR 9.39; 4.30-17.84). After the first year of follow-up, the overall cancer SIR associated with VTE and diabetes decreased to 1.05 (95% CI: 0.97-1.15). Conclusions VTE may be a marker of underlying cancer in patients with diabetes mellitus.