Objective We assessed the relationship between the levels of serum alkaline phosphatase, which is often increased with biliary obstruction and bone metastasis, and active cancer in patients with cryptogenic stroke. Methods Serum alkaline phosphatase levels in patients with cryptogenic stroke sampled upon admission were measured using the Japan Society of Clinical Chemistry method used in Japan. Active cancer was defined as a new diagnosis, treatment, progression, or recurrence within six months before admission or metastatic cancer. Multivariate logistic regression analyses were performed to explore the relationship between serum alkaline phosphatase and active cancer in these patients. Results Among the 249 patients classified as having cryptogenic stroke, 64 had active cancer. Patients with cryptogenic stroke with active cancer had significantly higher serum alkaline phosphatase levels (486±497 vs. 259±88.2 U/L; p<0.001) than those without cancer. Multivariate logistic analysis revealed that serum alkaline phosphatase levels ≥286 U/L were associated with cryptogenic stroke with active cancer [odds ratio (OR), 2.669, 95% confidence interval (CI), 1.291-5.517; p=0.008] independent of age ≤70 years old (OR, 3.303, 95% CI, 1.569-6.994; p=0.002), male sex (OR, 0.806, 95% CI, 0.380-1.710; p=0.573), and serum D-dimer levels ≥2.6 μg/mL (OR, 18.78, 95% CI, 8.130-43.40; p<0.001). Conclusion In patients with cryptogenic stroke, high serum alkaline phosphatase levels may be related to active cancer.
Keywords: alkaline phosphatase; cancer; cryptogenic stroke; stroke.