A Cohort Study of Incidences and Risk Factors for Thromboembolic Events in Patients with Idiopathic Membranous Nephropathy

Objective The aims of this study were to assess incidences and characteristics of arterial thromboembolic events (ATEs) and venous thromboembolic events (VTEs) in Chinese patients with idiopathic membranous nephropathy (IMN), and to identify the predisposing risk factors of them. Methods A total of 766 consecutive Chinese patients with IMN were enrolled in this retrospective cohort study. The cumulative incidences of newly diagnosed ATEs and VTEs were calculated using Kaplan-Meier methods. Univariable risk prediction model analysis followed by multivariable survival analysis was used to evaluate the potential risk factors of ATE and VTE. Results At 0.5, 1, 2, 3, and 5 years after biopsy diagnosis of IMN, the cumulative incidence of newly diagnosed ATEs were 4.3%, 5.7%, 6.3%, 7.1%, and 8.0%, and of newly diagnosed VTEs were 5.9%, 6.8%, 6.9%, 7.0%, and 7.2%, respectively. In 78 ATEs events (71 patients), cardiovascular diseases, thrombotic ischemic stroke (IS) and peripheral artery disease accounted for 50%, 45% and 5% respectively; in 60 VTEs events(53 patients), the deep vein thrombosis, renal vein thrombosis and pulmonary embolism accounted for 60%, 13% and 27% respectively. At the time of event, 42.1% patients with ATEs and 81.5% patients with VTEs were at nephrotic syndrome(NS) status (χ2=18.1, P<0.001). Severe proteinuria, aging, smoking, hypertension and prior ATE history were associated with ATEs. Aging was demonstrated as the independent risk factor for ATEs (P=0.001), and hypoalbuminemia was the dominant independent risk factor for VTEs (P=0.03). Conclusions Patients with IMN have increased incidences of ATEs and VTEs, and most of events occurred within the first 6 months of the disease. IS was very common in ATEs in our cohort. Severe proteinuria and classic risk factors for atherosclerosis were associated with onset of ATEs. Hypoalbuminemia independently predicted VTEs. Risks of both ATEs and VTEs were particularly high in the status of NS, particularly VTEs.