Efficacy and tolerance of selective and non-selective factor Xa inhibitors in the prevention of thrombosis in kidney disease in patients with systemic lupus erythematosus and antiphospholipid syndrome

Abstract

The use of factor Xa inhibitors is justified in the therapy of thrombosis in antiphospholipid syndrome (APS) and active lupus nephritis (LN). To monitor the efficacy and safety of these drugs, plasma anti-Xa (aXa) activity is determined. Objective : to assess the aXa activity of selective and non-selective factor Xa inhibitors in patients with systemic lupus erythematosus (SLE) and APS depending on how they affect the kidneys. Patients and methods. Clinical and laboratory findings were prospectively analyzed in SLE and APS patients who long received low molecular weight heparins (LMWHs) and selective Xa inhibitors, such as fondaparinux and rivaroxaban. The investigation enrolled 70 patients (54 females and 16 males) aged 39 years (range, 31 to 43 years) with SLE (n=15 (21%)), primary APS (PAPS) (n=10 (14%)), and SLE + APS (n=45 (65%)). Results . Kidney disease was diagnosed in 33 (47%) of the 70 patients. LN was detected in 15 (25%) of the 60 patients: 10 and 5 patients with SLE and SLE + APS, respectively. APS nephropathy (APSN) was manifested by elevated creatinine and urea levels with normal urine sediment and no history of glomerulonephritis and was observed in 18 (33%) of the 55 patients: in 16 with SLE + APS and 2 with PAPS. The therapeutic aXa range of 0.1—1.5 IU/ml was found in 43 (61%) of the 70 patients, low and high aXa activities were seen in 14 (20%) and 13 (19%) patients, respectively. In patients with APSN, the creatinine clearance (CC) depended on aXa levels: the highest CC was noted in patients with aXa >1.5 IU/mL, the lowest CC was in those with aXa <0.9 IU/ mL (p=0.046). The levels of aXa above the therapeutic range were more common in patients taking fondaparinux (9 (31%) out of the 29 patients) than in those using nadroparin (2 (7%) out of the 29 patients) (odds ratio (OR) 1.92; 95% confidence interval (CI), 1.25—2.97; p=0.04). In the fondaparinux group, high aXa was more frequently observed in patients with high SLE activity (7 (47%) out of the 15 patients) than in those with moderate or mild SLE activity (none out of the 7 patients) (OR 1.88; 95% CI, 1.17—3.01; p=0.037) and was unassociated with LN. The highest aXa level with no signs of hemorrhage was 2.08 IU/mL. Conclusion. The level of aXa is a qualitative laboratory marker for the efficacy and safety of LMWHs and fondaparinux. In patients with APS, the enhanced aXa activity of LMWHs and fondaparinux was associated with elevated CC and was not accompanied by hemorrhage. Fondaparinux is an effective and safe anticoagulant for the treatment and prevention of thrombosis in SLE and APS. The therapeutic window for aXa should be extended in these patients.