Abstract
Venous thromboembolism (VTE) is a life-threatening disease with risk of recurrence. Oral anticoagulation (OAC) with vitamin K antagonists (VKA) is effective to prevent thromboembolic recurrence. We aimed to investigate the quality of OAC of VTE patients in regular medical care (RMC) compared to a telemedicine-based coagulation service (CS). The thrombEVAL study (NCT01809015) is a prospective, multi-center study to investigate OAC treatment (recruitment: January 2011–March 2013). Patients were evaluated using clinical visits, computer-assisted personal interviews, self-reported data and laboratory measurements according to standard operating procedures. Overall, 360 patients with VTE from RMC and 254 from CS were included. Time in therapeutic range (TTR) was higher in CS compared to RMC (76.9% (interquartile range [IQR] 63.2–87.1%) vs. 69.5% (52.3–85.6%), p < 0.001). Crude rate of thromboembolic events (rate ratio [RR] 11.33 (95% confidence interval [CI] 1.85–465.26), p = 0.0015), clinically relevant bleeding (RR 6.80 (2.52–25.76), p < 0.001), hospitalizations (RR 2.54 (1.94–3.39), p < 0.001) and mortality under OAC (RR 5.89 (2.40–18.75), p < 0.001) were consistently higher in RMC compared with CS. Patients in RMC had higher risk for primary outcome (clinically relevant bleedings, thromboembolic events and mortality, hazard ratio [HR] 5.39 (95%CI 2.81–10.33), p < 0.0001), mortality (HR 5.54 (2.22–13.84), p = 0.00025), thromboembolic events (HR 6.41 (1.51–27.24), p = 0.012), clinically relevant bleeding (HR 5.31 (1.89–14.89), p = 0.0015) and hospitalization (HR 1.84 (1.34–2.55), p = 0.0002). Benefits of CS care were still observed after adjusting for comorbidities and TTR. In conclusion, anticoagulation quality and outcome of VTE patients undergoing VKA treatment was significantly better in CS than in RMC. Patients treated in CS had lower rates of adverse events, hospitalizations and lower mortality. CS was prognostically relevant, beyond providing advantages of improved international ratio (INR) monitoring.