Venous thromboembolism and suicide: a Danish nationwide case-control study

Venous thromboembolism has been associated with depression, but its relationship with suicide is uncertain.

To examine the association between venous thromboembolism and suicide risk.

This nationwide Danish case-control study (1996-2022) included individuals who died by suicide, each matched with 10 population controls by age and sex. Venous thromboembolism, identified from health registries, was exposure. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using conditional logistic regression, adjusting for socioeconomic factors, psychiatric and major somatic comorbidities.

We included 16 722 suicide cases and 167 220 controls. Venous thromboembolism was associated with a modestly increased risk of suicide (OR 1.18, 95% CI, 1.04-1.33). The association was strongest within the first month after venous thromboembolism, particularly among individuals without psychiatric comorbidity (OR 5.70, 95% CI, 1.95-16.64), whereas no clear increase was observed among those with psychiatric comorbidity. Between 1 and 12 months, risk remained elevated only among individuals without psychiatric comorbidity (OR 2.28, 95% CI, 1.47-3.53). After 12 months, no association was observed. Unprovoked venous thromboembolism was not associated with suicide, whereas provoked venous thromboembolism was associated with increased risk among individuals without psychiatric comorbidity (OR 1.58, 95% CI, 1.16-2.16). Associations were most evident in individuals without cancer and with low comorbidity burden.

Venous thromboembolism was associated with a modest increase in suicide risk. Although the number of events was limited, the association appeared strongest within the first months after diagnosis and among people without prior psychiatric comorbidity, but the absolute risk of suicide remained low.