Serum soluble ST2 is a potential long‐term prognostic biomarker for transient ischaemic attack and ischaemic stroke

Background and purpose Soluble ST2 (sST2) is a promising biomarker in inflammation, atherosclerosis and cardiovascular diseases. We investigated the association between serum sST2 and poor outcome in patients with transient ischaemic attack (TIA)/ischaemic stroke. Methods Patients within 24 h after onset and with measured serum sST2 were prospectively enrolled in this study. Poor outcome was a combination of a new stroke event (ischaemic or haemorrhagic) and all‐cause death within 90 days and 1 year. The associations of serum sST2 with poor outcome were analysed by Cox proportional hazards. Results Among the 430 patients included, the median (interquartile range) sST2 was 17.72 (9.31–28.84) ng/mL. A total of 19 (4.4%) and 38 (8.8%) patients experienced poor outcome within 90 days and 1 year, respectively. Compared with the lowest sST2 tertile, hazard ratios (HRs) [95% confidence intervals (CI)] for the highest tertile were 5.14 (1.43–18.51) for poor outcome within 90 days and 3.00 (1.29–6.97) at 1 year after multivariate adjustments. Adding sST2 to a prediction model significantly improved risk stratification of poor outcome in TIA/ischaemic stroke, as observed by the continuous net reclassification improvement of 60.98% (95% CI, 15.37–106.6%, P  = 0.009) and integrated discrimination improvement of 2.63% (95% CI, 0.08–5.18%, P  = 0.043) at 90 days and the continuous net reclassification improvement of 41.68% (95% CI, 8.74–74.61%, P  = 0.013) at 1 year. Conclusions Increased serum sST2 levels in TIA/ischaemic stroke were associated with increased risks of poor outcome within 90 days and 1 year, suggesting that serum sST2 may be a potential long‐term prognostic biomarker for TIA/ischaemic stroke.