Risk of venous thromboembolism in patients with psoriatic arthritis, psoriasis and rheumatoid arthritis: a general population-based cohort study

Aims To determine the risk of venous thromboembotism (VTE) defined as the combined endpoint of deep venous thrombosis (DVT) and pulmonary embolism (PE) among patients with psoriatic arthritis (PsA), psoriasis and rheumatoid arthritis (RA) compared with population controls. Methods and results A cohort study was conducted in a primary care medical record database in the UK with data from 1994-2014 among patients with PsA, RA, or psoriasis. Cox proportional hazards models were used to calculate the relative hazards for DVT, PE, and VTE. An interaction with disease modifying anti-rheumatic drugs (DMARD) was hypothesized a priori and was significant. Patients with PsA (n = 12 084), RA (n=51 762), psoriasis (n = 194 288) and controls (n = 1 225 571) matched on general practice and start date were identified. Patients with RA (with and without a DMARD prescription) and patients with mild psoriasis had significantly elevated risks of VTE (HR 135, 1.29, and 1.07, respectively) after adjusting for traditional risk factors. Severe psoriasis and PsA prescribed a DMARD had an elevated but not statistically significant risk for VTE. Findings were similar for DVT. The age-and-sex-adjusted risk of PE was elevated in RA, severe psoriasis and PsA patients prescribed a DMARD. Conclusion While systemic inflammation is a risk factor for VTE, the risk of VTE compared with controls is different among patients with three different inflammatory disorders: RA, PsA, and psoriasis.