Background: Renal impairment could be a risk factor for venous thromboembolism (VTE) recurrence and anticoagulation related bleeding in VTE patients. The objective of this study was to assess the effect of renal impairment on the risk of VTE recurrence, major bleeding and total health care costs in patients with acute VTE.
Methods: In this retrospective analysis of IMS PharMetrics PlusTM claims database, patients (≥18 years old) who had ≥ 1 inpatient or ≥ 2 outpatient VTE claims during January 2010-December 2013 (the index period) were identified. Patients who had continuous enrollment eligibility for at least 12 months before (baseline) and 12 months after (follow-up) the index date (first VTE claim) and had no VTE diagnosis and anticoagulant treatment during baseline period were included. Patients who required dialysis or had end stage renal disease were excluded. VTE patients with chronic kidney disease (stage I-IV or equivalent) during baseline based on ICD- 9 diagnosis codes were compared with those without renal impairment. Recurrent VTE was identified by inpatient or emergency department claims associated with VTE diagnosis after hospital discharge of the index VTE event or 7 days after index date for patients with index VTE events treated in the outpatient setting during the follow-up period. Major bleeding events were identified by inpatient claims with a bleeding diagnosis that occurred after an anticoagulant prescription fill among patients receiving anticoagulant therapy. Cox proportional hazards models adjusted for age, gender, index VTE type, health insurance type, outpatient anticoagulant therapy use, and baseline comorbidities was used to assess the risk of VTE recurrence and anticoagulation related major bleeding. Generalized linear model with gamma distribution and log link was used to evaluate the total health care costs (inclusive of medical and pharmacy costs) over the 1-year follow-up period adjusting for the same baseline characteristics.
Results: Of 20,873 eligible VTE patients (median age 57 years; 50% female), 238 had diagnosed renal impairment. Compared with patients without renal impairment, patients with renal impairment had higher rates for VTE recurrence (24% vs. 18%; adjusted hazard ratio (HR) = 1.32, 95% CI 1.06-1.63, p<0.01), and post anticoagulation major bleeding (4% vs 1%; HR=1.75, 95% CI 1.01-3.03, p=0.046). Patients with renal impairment had higher adjusted mean total health care costs ($41,283 vs. $30,757, p<0.01) than patients without renal impairment.
Conclusion: VTE patients with renal impairment had higher risk for VTE recurrence and major bleeding associated with anticoagulant therapy, resulting in increased utilization of health care resources than VTE patients without renal impairment.
Sponsorship: This research was funded by Daiichi Sankyo Inc, Parsippany, NJ.