Increased Serum Alkaline Phosphatase and Functional Outcome in Patients with Acute Ischemic Stroke Presenting a Low Ankle–Brachial Index

Aims: Elevated serum alkaline phosphatase (ALP) levels are associated with an increased risk of cerebrocardiovascular diseases. However, the associations of ALP with peripheral arterial disease (PAD) and outcomes in patients with acute ischemic stroke (AIS) are not well-known. Methods: We examined the association between ALP levels and the ankle–brachial index (ABI) in 2111 consecutive patients with AIS. A poor functional outcome was defined as a modified Rankin Scale (mRS) score of 3–6 at 3 months after stroke. A low ABI was defined as a value of ≤ 0.9. Results: Of the total cohort, 482 patients (22.8%) had a low ABI. ALP levels were higher in patients with a low ABI than in those without (p＜0.001). The multivariable logistic analysis revealed that quartiles of ALP levels were significantly associated with a low ABI (odds ratio [OR]: 1.20, 95% confidence interval [CI]: 1.08–1.33). Of the 1322 patients with a premorbid mRS score of 0–2, 434 patients (32.8%) had a poor outcome. The multivariable analysis revealed that elevated serum ALP levels and a low ABI were independently associated with poor stroke outcomes after adjustment for baseline characteristics (OR: 1.21, 95% CI: 1.07–1.38, and OR: 2.00, 95% CI: 1.40–2.84, respectively). Conclusions: Increased serum ALP levels are significantly associated with a low ABI. These indicators are independent prognostic factors for poor stroke outcomes at 3 months.