Atherogenic index of plasma and cognitive recovery trajectories after ischemic stroke: a retrospective longitudinal cohort study

Background Early cognitive recovery after ischemic stroke is heterogeneous. We examined global cognitive recovery trajectories and their associations with the atherogenic index of plasma (AIP) during and after inpatient rehabilitation. Methods This retrospective longitudinal cohort included 210 patients with imaging-confirmed ischemic stroke and available cognitive assessments at rehabilitation admission, discharge, and approximately 3 months after discharge. AIP was calculated from triglyceride and high-density lipoprotein cholesterol concentrations in the same first fasting blood sample collected within 24 h after rehabilitation admission. Latent class mixed models characterized Chinese Mini-Mental State Examination (CMMS) trajectories. Secondary, exploratory analyses examined AIP associations with trajectory membership and longitudinal CMMS and Modified Barthel Index (MBI) scores. Trajectory-membership analyses accounted for classification uncertainty using two-stage joint likelihood estimation with 1,000 parametric bootstrap draws. Results Three trajectories were identified: moderate-baseline marked-improvement (94 patients [44.8%]), higher-baseline modest-improvement (69 [32.9%]), and low-baseline persistently low (47 [22.4%]). In the fully adjusted model, each 1-SD higher AIP was associated with greater odds of the low-baseline persistently low trajectory versus the moderate-baseline marked-improvement trajectory (odds ratio, 1.85; 95% CI, 1.16–2.96; nominal p = 0.0095), but not versus the higher-baseline modest-improvement trajectory. Each 1-SD higher AIP was associated with 0.77 points less CMMS improvement from admission to follow-up (95% CI, −1.09 to −0.44; nominal p < 0.001). There was no clear association with longitudinal MBI recovery. Conclusion Early global cognitive recovery followed heterogeneous patterns. Higher rehabilitation-phase AIP was associated with less CMMS improvement and with the persistently low rather than the marked-improvement trajectory. These exploratory findings require independent replication; their clinical importance and prognostic utility remain uncertain.