Creatine Kinase Is Associated With Recurrent Stroke and Functional Outcomes of Ischemic Stroke or Transient Ischemic Attack

BACKGROUND: Many patients after stroke are found to have elevated serum creatine kinase (CK). This study aimed to investigate the associations between serum CK levels and clinical outcomes in patients with acute ischemic stroke or transient ischemic attack. METHODS AND RESULTS: The study included 8910 patients with acute ischemic stroke or transient ischemic attack from the CNSR‐III (Third China National Stroke Registry). Baseline serum CK levels after admission were measured. The associations between CK and clinical outcomes (stroke recurrence, death, and disability, defined as modified Rankin scale score 3–6 or 2–6) were analyzed. Patients with elevated CK levels had higher risks of recurrent stroke (hazard ratio [HR], 1.53; 95% CI, 1.21–1.93), death (HR, 1.68; 95% CI, 1.10–2.58), and disability (modified Rankin scale score, 3–6; odds ratio, 1.57; 95% CI, 1.29–1.90) at 3 months after adjusting confounding factors. Similar results were found at 1 year. The effects of CK on death and disability were more significant in male patients than female patients (P value for interaction <0.05). Elevated CK‐MB levels were not associated with clinical outcomes in this study. CONCLUSIONS: Elevated serum CK after ischemic stroke or transient ischemic attack is associated with higher risks of recurrent stroke, death, and disability at 3 months and 1 year. Serum CK may act as a useful predictor for recurrent stroke and poor functional outcomes in patients with acute ischemic stroke or transient ischemic attack. Sex modifies the relationship between elevated CK and disability or death.