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 anti-inflammatory treatment, possibly due to an unfavorable impact on RVO-related venous pathology.