Venous thromboembolism and risk of cancer in users of statins: A Danish population-based cohort study

Venous thromboembolism (VTE) may be the first symptom of cancer. Statins are suggested to prevent VTE, but the risk of cancer in VTE patients using statins remains poorly understood.

To examine if VTE is a marker of cancer in users of statins.

We identified all Danish patients during 1996-2017 with a first-time diagnosis of VTE and a filled prescription for a statin within 90 days prior to the VTE diagnosis. We classified patients as prevalent users if the first filling of a statin occurred more than one year preceding the VTE diagnosis, and as new users if the first filling occurred within the preceding year. We computed cumulative incidences of cancer, with death as a competing risk, and age-, sex-, and calendar-period standardized incidence ratios (SIRs), comparing the observed cancer incidence with the expected based on national cancer statistics.

Among 9280 (85%) prevalent users of statin and 1580 (15%) new users, the one-year cumulative incidence of any cancer was 6.6 (95% CI: 6.1-7.2) for prevalent users and 6.4 (95% CI: 5.2-7.6) for new users; the corresponding SIRs were 3.1 (95% CI: 2.9-3.3) and 3.5 (95% CI: 2.9-4.3). In the second and subsequent years, the SIRs diminished and approached unity for both prevalent (1.1 [95% CI: 1.1-1.2]) and new users (1.1 [95% CI: 0.9-1.3]).

VTE patients using statins had a 3-fold increased rate of cancer in the first year after diagnosis. A first VTE serves as an important marker of cancer, regardless of statin use.