Changes in treatment needs for chronic postoperative hypoparathyroidism during initiation of conventional treatment compared to stable phase of treatment

Abstract

Introduction: In our clinical experience, need for doses of active vitamin D and calcium supplements changes during the period following a diagnosis of postsurgical hypoparathyroidism (HypoPT), but only sparse data are available. In the present study, we aimed to investigate the magnitude of changes in need for activated vitamin D (alfacalcidol) and calcium supplements during initiation of therapy as well as time to be expected until a stable phase was achieved. Furthermore, we determined the frequency of (unexpected) episodes of hypo- and hypercalcaemia after reaching a steady state for alfacalcidol and calcium. Methods: Retrospective study of twenty-four patients with chronic postsurgical HypoPT (>6 months) diagnosed from 2016 to 2018. Data were extracted from medical records on doses of alfacalcidol and calcium as well as ionized plasma calcium levels (P-Ca2+) from time of diagnosis and until 86 weeks after surgery. Results: Patients were treated with alfacalcidol and calcium in order to maintain a stable concentration of P-Ca2+. Our data demonstrated a great variation in treatment needs until 11 weeks after surgery, where the mean doses of alfacalcidol stabilize, while calcium doses stabilized a bit earlier. After the stable phase had emerged, 21 out of 24 patients continued to have one or more episodes of spontaneous hypo- or hypercalcaemia. Conclusions: Patients with chronic HypoPT attain a steady state for alfacalcidol 11 weeks after the diagnosis. Continuous monitoring of P-Ca2+ is of continued importance after reaching steady state due to a high frequency of spontaneous hypo- or hypercalcaemia.