Alkaline Phosphatase and Outcomes in Patients With Preserved Renal Function: Results From China National Stroke Registry.

BACKGROUND AND PURPOSE: Alkaline phosphatase (ALP) is associated with risk of adverse cardiovascular events in patients with kidney failure. However, there is little data about effects of ALP on stroke outcomes in patients with preserved kidney function. The study aimed to explore the association between serum ALP level and clinical outcomes after stroke in patients with preserved kidney function.

METHODS: We included 16 367 stroke patients with preserved kidney function from the China National Stroke Registry for current analysis. Serum ALP levels were tested by automated enzymatic method using unfrozen samples in each center. Participants were divided into 5 groups according to ALP quintiles. Composite end point comprised of recurrent stroke, myocardial infarction, other ischemic vascular events, and all-cause mortality. Poor functional outcome is defined as modified Rankin Scale score of 3 to 6. Multivariable logistic regression was used to evaluate the independent association of serum ALP with 1-year all-cause mortality, recurrent stroke, composite end point, and poor functional outcome.

RESULTS: The mean age of the included 16 367 patients was 63.9 years, and 63.3% of them were men. Among the top ALP quintile (>98.0 U/L), 1-year incidences of all-cause mortality, recurrent stroke, composite end point, and poor functional outcome were 12.6%, 5.7%, 14.4%, and 27.0%, respectively. Compared with the lowest ALP quintile (≤59.0 U/L), the adjusted odds ratios of the top quintile were 1.36 (1.10-1.68) for all-cause mortality, 1.45 (1.11-1.90) for stroke recurrence, 1.35 (1.12-1.63) for composite end point, and 1.36 (1.17-1.60) for poor functional outcome. There was no significant interaction between age, sex, or alcohol consumption and ALP ( P for interaction ≥0.10) for all outcomes.

CONCLUSIONS: In patients with preserved kidney function, ALP may be an independent predictor of all-cause mortality, stroke recurrence, composite end point, and poor functional outcome after stroke.