High alkaline phosphatase levels in hemodialysis patients are associated with higher risk of hospitalization and death

Abstract

We evaluated risks associated with elevated alkaline phosphatase in hemodialysis patients using longitudinal data from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of hemodialysis patients in 12 countries. Alkaline phosphatase levels were normalized by the upper limit of the laboratory-reported reference range. Cause-specific hospitalization and mortality risks were evaluated using Cox proportional hazards models, stratified by region and adjusted for phosphorus, calcium, albumin, parathyroid hormone, case mix, and numerous comorbidities. The odds of high normalized alkaline phosphatase were increased twofold in the United States in comparison to Japan. Elevations of normalized alkaline phosphatase were significantly associated with several comorbid conditions, increased fractures, parathyroidectomy, risk of hospitalization due to major adverse cardiac events, higher all-cause cardiovascular, and infection-related mortality risk. Our results also show that elevated serum normalized alkaline phosphatase was associated with higher risks of hospitalization and death in hemodialysis patients, independent of calcium, phosphorus, and parathyroid hormone levels.