The Interaction Between Venous Thromboembolism and Socioeconomic Status on the Risk of Disability Pension

BACKGROUND: Venous thromboembolism (VTE) is associated with increased risk of disability pension. How socioeconomic status (SES) impacts the risk of disability pension after a VTE is unknown. The aim of this nationwide population based cohort study to investigate the interaction between SES and incident VTE on the risk of subsequent disability pension. METHODS: Using Danish national medical and administrative databases, we established a nationwide cohort of 41,781 individuals aged 25–65 years with incident VTE during 1995–2016 and a comparison cohort (n=208,905) from the general population matched on year of birth, sex, and calendar year of VTE. We computed incidence rates (IRs) as the number of disability pension events per 1000 person-years at risk and measured the interaction between VTE and levels of SES (high, medium, low) on an additive scale by calculating interaction contrasts (difference in IR difference). RESULTS: Among individuals with high SES, the disability pension IR per 1000 person-years was 5.4 (95% CI: 4.8–6.1) in the VTE cohort and 1.6 (95% CI: 1.5–1.7) in the comparison cohort (IR difference 3.8). The corresponding disability pension IR in individuals with low SES was 55.1 (95% CI: 52.1–58.1) in the VTE cohort and 26.1 (95% CI: 25.1–27.1) in the comparison cohort (IR difference 24.0). An interaction contrast of 25.1 indicated that interaction accounted for 45.6% (25.1/55.1) of the disability pension IR in individuals with VTE and low SES. CONCLUSION: SES and VTE interact to increase the risk of disability pension after VTE beyond their independent effects.