The ZJU index as a novel predictive tool for post-stroke cognitive impairment: a prospective cohort study

The ZJU index serves as a composite metabolic biomarker associated with metabolic dysregulation. Its relationship with post-stroke cognitive impairment (PSCI) remains unestablished. This study aims to elucidate the association between ZJU index and PSCI incidence. We enrolled 261 patients with acute mild ischemic stroke. PSCI was defined as Mini-Mental State Examination < 27 at the 6–12 months follow-up. We collected clinical and laboratory data and calculated the ZJU index at baseline. ZJU index was dichotomized according to the prespecified cut-off points 36.13 for the high and low groups. Binary logistic regression and linear regression analyses were performed to analyze the association between ZJU index and cognitive outcomes. Predictive models incorporating ZJU index as continuous or categorical variables were developed, and a nomogram was constructed and validated. Bootstrap internal validation was performed to correct for optimism. The results revealed that ZJU index was significantly higher in the PSCI group. Higher ZJU index was an independent risk factor for PSCI (OR = 1.104, 95% CI = 1.032–1.181, P = 0.004) and associated with worse cognitive functions. The model using ZJU index as a continuous variable showed good discrimination (AUC = 0.736, 95% CI = 0.660–0.807), outperforming the categorical model (AUC = 0.709, 95% CI = 0.645–0.774) according to the net reclassification improvement and integrated discrimination improvement value. Bootstrap internal validation confirmed model stability (optimism‑corrected AUC = 0.711, 95% CI = 0.690–0.720). In conclusion, elevated ZJU index is independently associated with PSCI and may serve as a practical tool for early risk stratification.