Antiphospholipid antibodies in lupus nephritis – a single centre experience

Abstract

INTRODUCTION AND AIMS: The clinical significance of antiphospholipid antibodies (APA) in lupus nephritis (LN) remains to be defined. METHODS: We retrospectively reviewed 149 LN patients who were followed at the SLE clinic of Queen Mary Hospital, Hong Kong during 2000-2017, and compared the long-term clinical outcomes between patients seropositive or seronegative for APA. RESULTS: 53 patients (35.6%) were seropositive for APA and 96 (64.4%) were seronegative, and were followed for 150.3±63.4 and 158.9±59.8 months respectively. The sero-prevalence rates for anti-cardiolipin IgM, anti-cardiolipin IgG, anti-β2 glycoprotein I and lupus anticoagulant were 18.8%, 18.1%, 10.7% and 8.1% respectively. APA-seropositive patients showed inferior long-term patient survival (91% and 85% at 10- and 15-year respectively, compared with 99% and 95% in APA-seronegative patients, p=0.043, Figure 1, A). Six APA-seropositive patients died, four because of thrombotic events and two because of bleeding complications related to anti-coagulation. Three APA-seronegative patients died, two due to pneumonia and one due to bowel ischemia. APA-seropositive LN patients also showed more rapid decline in eGFR (-1.44 mL/min/year, compared with -0.38 mL/min/year in APA-seronegative patients, p=0.027) and inferior long-term renal survival (82% and 74% at 10- and 15-year respectively, compared with 91% and 87% in APA-seronegative patients, p=0.034; Figure 1, B). The APA-seropositive group also had higher incidence of thrombotic events and miscarriage (32.1% and 13.2%, compared with 16.7% and 2.1% in the APA-seronegative group respectively, p=0.030 and 0.006). CONCLUSIONS: APA-seropositivity was associated with inferior long-term patient and renal survival, and more frequent thrombotic events and miscarriage in LN patients.