Serum Phosphate and Calcium Should Be Primarily and Consistently Controlled in Prevalent Hemodialysis Patients

Abstract Mineral metabolism affects mortality in hemodialysis patients and is identified by imbalances in serum phosphate ( P ), calcium ( Ca ), and parathyroid hormone ( PTH ). We examined associations between annual mineral values ( P , Ca , PTH ) and mortality in a 3‐year cohort ( D ec 2006–2009) of 128 125 hemodialysis patients using three models, that is, baseline, time‐dependent and time‐average C ox models. We also examined associations between achieved Japanese guideline targets ( P : 3.5−6.0 mg/d L , corrected C a 8.4−10.0 mg/d L , intact PTH 60−180 mg/d L ) and all‐cause survival to elucidate which parameter should be controlled as a priority. High and low serum P (>6.0 or ≤3.5 mg/d L ), high Ca (>9.5 mg/d L ), higher PTH (>300 pg/m L ) and lower PTH (≤60 pg/m L ) were significantly associated with high mortality in all three models ( P < 0.01). When we examined the association between combination of mineral targets and mortality, patients who achieved all targets simultaneously (20% of subjects, reference) showed lowest mortality. Those who achieved both P and Ca targets showed the same mortality as the reference group. Those who only met P target had a lower risk of death (hazard ratio = 1.17) compared to those that achieved Ca or PTH target (1.41, 1.47, respectively). As time of achieving P and Ca targets increased, all‐cause mortalities diminished incrementally, significantly. Mineral metabolism disorder would lead to high mortality in prevalent hemodialysis patients. Among mineral values, P would be the strongest predictor for high mortality. Consistent achievement of P and Ca targets would lead to good survival.