Venous Thromboembolism in Patients With Reduced Estimated GFR: A Population-Based Perspective

BACKGROUND: An increased frequency of venous thromboembolism (VTE) has been shown in patients with decreased kidney function measured by decreased estimated glomerular filtration rate (eGFR). However, present practices with respect to VTE prevention and management in patients with decreased eGFR in general population settings are uncertain. STUDY DESIGN: Observational study. SETTING & PARTICIPANTS: Community investigation of 1,509 metropolitan Worcester, MA, residents with a validated VTE in 1999, 2001, and 2003 with further follow-up for up to 3 years. PREDICTOR: Patients with VTE classified further according to eGFR on presentation: <30, 30-59, 60-89, or ≥90 mL/min/1.73 m(2) (reference group). OUTCOMES: Recurrent VTE, major bleeding episodes, and all-cause mortality. MEASUREMENTS: Demographic and clinical characteristics, treatment practices, and study outcomes were extracted from patients' hospital and outpatient medical records; eGFR was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. RESULTS: Patients with VTE with eGFR <30 mL/min/1.73 m(2) were at increased risk of recurrent VTE (HR, 1.83; 95% CI, 1.03-3.25), major bleeding episodes (HR, 2.30; 95% CI, 1.28-4.16), and all-cause mortality (HR, 1.70; 95% CI, 1.12-2.57) during a 3-year follow-up. Patients with decreased eGFR also presented with more comorbid conditions and were less likely to be discharged on any form of anticoagulant therapy (72.6%, 81.0%, 82.1%, and 87.3% for eGFR <30, 30-59, 60-89, and ≥90 mL/min/1.73 m(2), respectively; P < 0.001). LIMITATIONS: Decreased eGFR status is presumed based on creatinine values on clinical presentation. The impact of drug dosage, timing, type of anticoagulant therapy, and medication adherence on study outcomes could not be evaluated. CONCLUSIONS: Severe decreases in eGFR are associated with increased risk of long-term recurrent VTE, bleeding, and total mortality in patients with VTE. A greater frequency of serious comorbid conditions, difficulties implementing available management strategies, and suboptimal VTE prophylaxis during hospital admissions likely contributed to our findings.