Higher Adherence to Treatment With Low-Molecular-Weight-Heparin Nadroparin Than Enoxaparin Because of Side Effects in Cancer-Associated Venous Thromboembolism

Current guidelines recommend low-molecular-weight-heparins (LMWH) monotherapy for 3 to 6 months as first-line treatment for cancer-associated venous thromboembolism (VTE). In clinical practice, enoxaparin and nadroparin are common agents used. However, differences in therapy adherence between these LMWHs have never been reported. Therefore, our aim was to compare adherence to enoxaparin and nadroparin in patients with cancer-associated VTE. Consecutive patients with active cancer and objectively confirmed VTE, treated at a Dutch or a Spanish hospital, were followed during LMWH therapy with a maximum of 180 days. Cumulative incidences of discontinuation of both LMWHs were estimated and compared according to the Kaplan-Meier method, applying a competing risk analysis to correct for mortality. A total of 366 patients were analyzed during LMWH treatment, of whom 284 patients (78%) were treated with enoxaparin and 82 (22%) with nadroparin. The cumulative incidence of discontinuation of enoxaparin and nadroparin treatment because of side effects was 30% (95% confidence interval [CI] 24–36) and 8.8% (95% CI 1.1–15), respectively. Competing risk analysis revealed a higher number of patients discontinuing enoxaparin due to side effects (adjusted hazard ratio [HR]: 2.8; 95% CI 1.06–7.2). Pain at the injection site was the most common reason of discontinuation in patients using enoxaparin, occurring in 32 patients, while it occurred in 1 patient using nadroparin (adjusted HR: 4.0; 95% CI 0.52–31). This analysis reveals that enoxaparin was associated with a higher risk of discontinuation because of side effects compared to nadroparin. However, given the nature of the patient groups, these findings should be followed by future studies.