Clinical effectiveness of a multidisciplinary thrombosis service versus usual care in the management of venous thromboembolism: A retrospective cohort study

Introduction: Venous thromboembolism (VTE) is a common, potentially life-threatening condition. To improve care, a multidisciplinary Adult Outpatient Thrombosis Service (TS) was implemented in one region of Newfoundland and Labrador, Canada. This study evaluated the clinical effectiveness of the TS compared to usual care (UC) for patients with newly diagnosed VTE. Method: We conducted a retrospective cohort study of adults with objectively confirmed VTE between 2017 and 2019. Patients managed by the TS were compared to those receiving UC. Data were obtained from linked administrative and clinical databases. Propensity score matching was applied to control for confounding. Primary outcomes included recurrent VTE and major bleeding. Secondary outcomes were all-cause hospitalizations, emergency department visits, and all-cause mortality. Incidence rate ratios (IRR) and 95% CIs were calculated using Poisson regressions; Cox models were used for mortality. Results: A total of 1499 patients were included (TS: n = 464; UC: n = 1035). The TS group experienced significantly lower rates of adverse outcomes. VTE recurrence (IRR = 0.65, 95% CI: 0.29–0.67, p = < 0.001) and major bleeding (IRR = 0.33, 95% CI: 0.19–0.53, p = 0.011) were significantly reduced in the TS group, as were hospitalizations (IRR = 0.76, 95% CI: 0.64–0.92, p = 0.009). No significant difference was found in emergency department visits (IRR = 1.02, 95% CI: 0.79–1.32, p = 0.848). All-cause mortality was also lower (HR = 0.62, 95% CI: 0.48–0.81, p = 0.0004). Conclusion: Management of VTE within a multidisciplinary TS was associated with significantly lower rates of complications, hospitalizations, and all-cause mortality compared to UC. These findings suggest that a structured, specialized outpatient thrombosis care model may be associated with favorable clinical outcomes in real-world settings.