Chronic inflammatory diseases increase the risk of post-thrombotic syndrome: A prospective cohort study

Background: Clinical management of patients with deep vein thrombosis (DVT) is centered around their risk of recurrent venous thromboembolism (VTE) and post-thrombotic syndrome (PTS). While chronic inflammatory disease (CID) has been established as a risk factor of (recurrent) VTE, research about its potential impact on PTS is lacking. Objectives: We aimed to assess the risk of PTS in patients with CID, stratifying for the use of anti-inflammatory treatment. Patients/Methods: Consecutive patients with proximal DVT and no active cancer between 2003 and 2018 received a two-year prospective follow-up. CID included inflammatory bowel disease, rheumatic diseases, and gout. Residual venous obstruction (RVO) was assessed by compressive ultrasound after 3-6 months. PTS was diagnosed using the Villalta score after 6-24 months. Hazard ratios (HR) and odds ratios (OR) were adjusted for patient characteristics. The medical ethics committee approved this study. Results: In total 82 of 801 patients had CID (10.2 %). PTS more often developed in patients with CID (35.4% vs. 18.9 %, p < 0.001) than in those without CID (HR 1.72 [1.15-2.58]). The prevalence of RVO was similar in patients with and without CID (36.8% vs. 41.4 %), and RVO was strongly associated with PTS in patients with CID (OR 3.21 [1.14-9.03]). Moreover, patients with untreated CID (44 %, n = 36) more often had RVO than those with treated CID (51.6% vs. 26.7 %, p = 0.027), and accordingly had a higher risk of PTS (HR 2.18 [1.04-4.58]). Conclusions: Patients with CID had an increased risk of developing PTS, especially those without antiinflammatory treatment, possibly due to an unfavorable impact on RVO-related venous pathology.