Renal Function Affects Prognostic Role of Antiphosphatidylserine Antibodies for Acute Ischemic Stroke Patients

Abstract

Background: Whether the renal function influences the association between antiphosphatidylserine antibodies (aPS) and prognosis of ischemic stroke remains unclear. We aimed to investigate the prognostic value of aPS after ischemic stroke stratified by renal function status. Methods: This prospective study was based on China Antihypertensive Trial in Acute Ischemic Stroke, a randomized clinical trial in 26 hospitals across China from August 2009 to May 2013. A total of 2,874 ischemic stroke patients with blood samples or baseline records of estimated glomerular filtration rate (eGFR) were included in this study. Serum aPS levels were quantitatively measured at baseline, and abnormal renal function in this study was defined as eGFR <90 mL/min per 1.73 m2. The primary outcome was a combination of death and major disability (modified Rankin Scale score ≥3) at 3 months after stroke. Secondary outcomes were death and major disability separately. Results: The association between aPS and primary outcome was significantly modified by renal function status (p for interaction = 0.02). After adjustment for covariates, increased aPS were significantly associated with the primary outcome in the patients with abnormal renal function (OR 2.09; 95% CI 1.24–3.53; p for trend = 0.006), but not in those with normal renal function (OR 0.92; 95% CI 0.69–1.23; p for trend = 0.59), when 2 extreme tertiles were compared. Furthermore, multiple-adjusted spline regression model showed a linear association between aPS and risk of primary outcome in the patients with abnormal renal function (p for linearity = 0.02) but not in those with normal renal function (p for linearity = 0.71). Conclusions: Increased aPS were positively and independently associated with death or major disability after acute ischemic stroke in the patients with abnormal renal function.