PB1451 - Chronic inflammatory diseases increase the risk of recurrent venous thromboembolism irrespective of anti-inflammatory treatment

Background: Chronic inflammatory diseases (CIDs) are known to increase the risk of venous thromboembolism (VTE), but it is uncertain whether they also increase the risk of recurrent VTE. While D-dimer is an established marker to assess recurrence risk, its levels might be less reliable in the context of CIDs. Recurrence risk might instead be related to disease activity, reflected by the use of anti-inflammatory treatment and C-reactive protein (CRP) levels.

Aims: We assessed recurrence risk and potential risk factors in patients with CIDs.

Methods: Consecutive patients with proximal DVT were followed for two years after stopping anticoagulant therapy between 2003 and 2020. CIDs included inflammatory bowel disease (IBD), rheumatic diseases, and gout. Patients with active malignancy were excluded. D-dimer and CRP were measured one month after stopping anticoagulant therapy with clinical cut-offs at 500 mg/L and 5.0 mg/L, respectively. Hazard ratios (HRadj) were calculated by Cox regression adjusted for relevant patient characteristics. The medical ethics committee approved this study.

Results: In total 55 of 564 patients (9.8%) had CIDs. Baseline characteristics were similar except for age and DVT provoked by surgery (Table 1). Patients with CIDs experienced more recurrent VTE (25.5 vs. 11.5%, p=0.003) than those without CIDs (Figure 1A; HRadj 2.17 [1.22-3.87]), especially patients with IBD (HRadj 5.14 [2.22-11.89]). Patients with CIDs had higher levels of D-dimer (615 [342-1147] vs. 441 [291-729], p=0.016) and CRP (4.6 [2.0-7.0] vs. 3.0 [1.0-5.9], p=0.014) than those without CIDs. Within patients with CIDs, recurrence risk was strongly associated with high D-dimer levels (Figure 1B; HRadj 5.14 [1.16-22.79]), but not with anti-inflammatory treatment (HRadj 0.67 [0.24-1.92]) or high CRP levels (HRadj 1.14 [0.40 -3.25]).

Conclusion(s): Patients with CIDs had an increased recurrence risk, which did not seem to be reduced by anti-inflammatory treatment. Despite elevated inflammation in patients with CIDs, D-dimer was still an excellent predictor of recurrent VTE.