Elevated Serum Alkaline Phosphatase as a Predictor of Cognitive Impairment in Patients With Acute Ischaemic Stroke: A Retrospective Cohort Study

Background: In the present study, we assessed the relationship between serum alkaline phosphatase (ALP) levels and cognitive function changes in acute ischaemic stroke patients.

Methods: We retrospectively collected the demographic data and clinical information from the medical records of patients after the onset of ischaemic stroke. We used the Chinese version of the Mini-Mental State Examination to assess cognitive function. Mixed linear and logistic regression models adjusted for several factors were used to explore the relationship between ALP and cognitive impairment.

Results: A total of 1019 patients were included in the analysis, including 523 poststroke patients with cognitive impairment (PSCI) and 496 patients with non-PSCI. The incidence of poststroke cognitive impairment was 51.3 %. The serum ALP level in the PSCI group was significantly higher than that in the non-PSCI group (86.5 ± 18.9 U/L vs 68.6 ± 15.5 U/L, P < 0.001). The mixed linear model fully adjusted for all variables indicated that the ALP level was positively associated with cognitive impairment (based on the Mini-mental State Examination score) decline, with changes from -0.54 to -0.16 per unit increase in ALP. The logistic regression revealed that the odds of cognitive impairment increased by 42 % when the ALP concentration increased by one U/L (odds ratio (OR) = 1.42, 95 %CI: 1.17-3.09, P = 0.012). The spline regression model further confirmed the dose-response relationships between ALP levels and three-month cognitive impairment (P for nonlinear trend = 0.012).

Conclusion: The present study revealed that relatively high serum ALP levels at baseline might be an independent risk factor for cognitive impairment in patients with acute ischaemic stroke.

Keywords: Cognitive impairment; Ischemic stroke; MMSE score; Prospective study; serum alkaline phosphatase.