Therefore, the present study compared the efficacy of two maintenance therapy protocols for patients with SHPT who responded to initial OCT therapy, resulting in the control of iPTH to <150pg/mL. One was oral administration of alfacalcidol (an oral vitamin D preparation) at a dose of 1.0 μg/day (higher-dose group) and the other was at a dose of 0.25 μg/day (lower-dose group), both of which are clinically effective doses for HD patients with SHPT.