Elevated serum alkaline phosphatase as a predictor of cognitive impairment in patients with acute ischaemic stroke: A retrospective cohort study

Abstract

BackgroundIn the present study, we assessed the relationship between serum alkaline phosphatase (ALP) levels and cognitive function changes in acute ischaemic stroke patients. MethodsWe 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. ResultsA 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). ConclusionThe 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.