Admission high-sensitivity cardiac troponin T and clinical outcomes after acute ischemic stroke: a retrospective cohort study with exploratory nonlinear analysis

Background Elevated high-sensitivity cardiac troponin T (hs-cTnT) is frequently observed in patients with acute ischemic stroke (AIS) and has been associated with adverse outcomes. We aimed to evaluate the association of admission hs-cTnT with 90-day functional outcome and all-cause mortality during follow-up, with particular attention to potential nonlinear risk patterns across the biomarker range. Methods This single-center retrospective cohort study included 564 patients with AIS admitted between January 2022 and October 2024. The primary outcomes were modified Rankin Scale (mRS) at 90 days and long-term all-cause mortality. Multivariable logistic regression was used for poor 90-day functional outcome and Cox proportional hazards models were used for all-cause mortality during follow-up. Restricted cubic spline (RCS) analyses were performed to explore nonlinear dose–response relationships, and segmented regression models were used to estimate exploratory turning points. Results Among 564 patients, 212 (37.6%) had elevated hs-cTnT (>14 ng/L). Elevated hs-cTnT was independently associated with poor 90-day mRS (adjusted OR 1.93, 95% CI, 1.22–3.05; p = 0.005) and all-cause mortality during follow-up (fully adjusted HR 4.12, 95% CI, 2.31–7.48; p < 0.001). During a median follow-up of 17 months (IQR 12–26 months), Kaplan–Meier analysis demonstrated significantly lower overall survival in patients with elevated hs-cTnT ( p < 0.001). RCS analysis revealed significant nonlinear associations between hs-cTnT and both endpoints ( p < 0.001). Exploratory model-derived turning points were observed at 28.42 ng/L for functional outcome and 31.68 ng/L for mortality; these should be interpreted as exploratory rather than validated clinical cutoffs. Below these values, risk increased more steeply; above them, no statistically significant further increase in risk was observed. Conclusion Admission hs-cTnT was independently associated with 90-day functional outcome and all-cause mortality during follow-up in patients with AIS. The association appeared to be nonlinear, with model-derived turning points at approximately 28–32 ng/L that should be interpreted as exploratory rather than definitive clinical cutoffs. Clinically, hs-cTnT may be useful as a complementary marker for identifying patients at higher risk who may warrant closer neuro-cardiac evaluation, although its incremental predictive value has not been formally assessed.