Mineral Metabolism Markers Are Associated with Myocardial Infarction and Hemorrhagic Stroke but Not Ischemic Stroke in Hemodialysis Patients: A Longitudinal Study

BACKGROUND/AIMS The associations between phosphate, calcium, and intact parathyroid hormone (PTH) levels and composite cardiovascular end points have been studied. This study examined the associations of these markers with myocardial infarction (MI) and stroke separately. METHODS This is a longitudinal study on 65,849 hemodialysis patients from the Japan Renal Data Registry. Patients with prior events at baseline were excluded. Predictors were phosphate, albumin-corrected calcium, intact PTH, and calcium times phosphate product levels. Outcome was the first episode of MI or stroke during a 1-year observation period. Data were analyzed using multiple logistic regression analyses, adjusted for potential confounders. RESULTS There were 1,048, 651, and 2,089 events of incident MI, hemorrhagic, and ischemic stroke, respectively. Incident MI was associated with phosphate levels ≥6.5 mg/dL (odds ratio 1.49; confidence interval 1.23-1.80) compared with phosphate levels of 4.7-5.4 mg/dL and intact PTH levels>500 pg/mL (1.35; 1.03-1.79) compared with intact PTH levels of 151-300 pg/mL. Higher albumin-corrected calcium level was positively associated with MI (p = 0.04 by trend analysis). Hemorrhagic stroke was associated only with intact PTH levels>500 pg/mL (1.54; 1.10-2.17). Incident ischemic stroke had no association with phosphate, calcium, or intact PTH levels. The association of calcium times phosphate product with outcomes was essentially the same pattern as that of phosphate and outcomes. CONCLUSIONS MI was associated with phosphate, calcium, and intact PTH levels, whereas hemorrhagic stroke was associated only with intact PTH. Ischemic stroke was not associated with any of them. The potential distinct beneficial effect on MI and stroke by managing bone and mineral disease should be investigated in future studies.