Adherence to Anticoagulant Therapy in Pediatric Patients Hospitalized With Pulmonary Embolism or Deep Vein Thrombosis: A Retrospective Cohort Study

Objectives: The American College of Chest Physicians recommends anticoagulant therapy for at least 3 months in children hospitalized for venous thromboembolism. The objectives of the study were to evaluate the medication utilization patterns and predictors of adherence to anticoagulant therapy in pediatric population. Methods: Texas Medicaid medical and prescription claims from September 1, 2007 to December 12, 2012 were extracted for children (<18 years) hospitalized for pulmonary embolism (PE) or deep vein thrombosis (DVT). The index date was defined as the date of the first prescription of an anticoagulant given within 14 days of discharge. Proportion of days covered (80% vs <80%) was used to assess adherence to anticoagulants while controlling for demographics, cause of hospitalization, history of nonsteroidal anti-inflammatory drug use, anticoagulant use, malignancy, drug type, and Charlson comorbidity index (CCI). Key Findings: The patients (n = 60) had a mean ( standard deviation [SD]) age of 14.2 (+/- 4.8) years, were primarily female (56.7%), African American (55.0%), enoxaparin users (58.3%), and had a mean (+/- SD) CCI of 18.3 (+/- 37.7). The mean (+/- SD) adherence rates for warfarin and enoxaparin were 85.5% (+/- 22.7%) and 78.7% (+/- 27.8%), respectively. Overall, 66.7% were adherent (80%) to anticoagulant therapy. Logistic regression showed that increasing age was significantly associated with adherence to anticoagulant therapy, after controlling for other covariates (odds ratio = 1.5, 95% confidence interval = 1.13-1.85). Conclusion: Nearly one-third of the pediatric patients on anticoagulant therapy after discharge from PE or DVT were still nonadherent. Further research is needed to highlight the factors responsible for nonadherence in pediatric patients.