Risk of venous thromboembolism in patients with mycosis fungoides and parapsoriasis: A Danish nationwide population-based cohort study.

BACKGROUND

Mycosis fungoides (MF) and parapsoriasis are characterized by malignant proliferation and chronic inflammation, which may affect the risk for venous thromboembolism (VTE).

OBJECTIVES

To examine the risk for VTE in patients with MF and parapsoriasis.

METHODS

We conducted a nationwide population-based cohort study in Denmark to examine the relative risk (RR) of VTE in 525 patients with MF and 634 patients with parapsoriasis compared with that in sex- and age-matched controls from the general population.

RESULTS

In patients with MF, the 10-year absolute risk for VTE was 3.4% (95% confidence interval [CI], 2.0-5.4). The adjusted RRs were 2.41 (95% CI, 1.49-3.90) for VTE and 4.01 (95% CI, 2.16-7.46) for pulmonary embolism. Notably, within the first 5 years after diagnosis with MF, the RR of pulmonary embolism was increased 6.7-fold (to 6.71 [95% CI, 2.86-15.72]). Patients with parapsoriasis had a 2.7-fold increased RR of VTE (to 2.67 [95% CI, 1.32-5.40]) in the absence of other established VTE risk factors.

LIMITATIONS

We had no information regarding disease stage of MF and prescribed drugs.

CONCLUSION

Patients with MF and parapsoriasis had an increased RR of VTE, although the absolute risk remained low. These findings should increase awareness of comorbidities in patients with MF and parapsoriasis.