Clinical Burden and Practice Patterns in Patients With Chronic Hypoparathyroidism in the United States (US): A Claims Data Analysis Using Surgery-Based Criteria
Authors: Sharma Dolly , Deering Kathleen L , Loustau Patrick , Culler Michael D , Allas Soraya , Weiss Blandine , Mitchell Deborah M , Astolfi Danette , Mannstadt Michael 
Published: May 2021

Abstract
Objectives: Significant knowledge gaps exist regarding the clinical burden and practice patterns associated with chronic hypoparathyroidism (cHP). This study assessed the clinical burden and practice patterns in patients with cHP identified using surgery-based criteria.
Methods: This retrospective cohort study was conducted using a large (130 million individuals) US claims database, the HealthVerity Closed Payer Claim Medical and Pharmacy database (Private Source 20) from Oct 2014 to Dec 2019. The patient eligibility criteria for the surgery-based method included the presence of a procedure claim of either parathyroidectomy, complete or partial thyroidectomy, or neck dissection, followed by a HP diagnosis claim (6–15 months apart) with a subsequent second HP diagnosis claim at any time point, and with continuous enrollment for 15 months before the index date (the date of the first qualifying HP diagnosis claim) and ≥6 months after. Patients were followed one year before the surgery and up to two years after the index date. Patient characteristics, comorbidities, laboratory testing and treatment patterns were descriptively analyzed.
Results: A total of 1,406 patients met the eligibility criteria, among which 1,184 patients had complete data for 1-year follow-up. The mean age was 52.1 + 16.4 (SD) years, and 83.2% were females. The mean time between surgery and qualifying HP diagnosis claim was 8.7 + 2.3 (SD) months, and 115 patients (8.2%) had a HP diagnosis prior to surgery. During the 1-year follow-up, the most common comorbidities were cancer (54.2%, of which 49% were thyroid cancers), hypertension (49.7%), hypocalcemia (47.1%), chronic pulmonary disease (21.9%), diabetes (21.7%), cardiac arrhythmias (18.4%), CKD stage 3–5 (11.3%), osteoporosis (9.8%), and neuropsychiatric disorders, including anxiety (23.9%), depressive disorders (21.8%), and sleep-wake disorders (20.9%). Most cHP patients were monitored for lab values. These included serum calcium (93.2%), eGFR/creatinine (86.2%), 25-Hydroxy Vitamin D (66.5%), intact PTH (63.0%), serum magnesium (40.9%), serum phosphorous (38.4%), bone mineral density (9.8%), and 24h-urine calcium (8.4%) during the 1-year follow up. Also within the 1-year follow-up, 66.9% of patients had a prescription claim for thyroid replacement therapy, 51.6% for calcitriol, 13.3% for ergocalciferol, and 5.5 % for PTH.
Conclusion: This cHP population, identified using surgery-based criteria, largely consists of patients with a recent diagnosis, and had a substantial comorbidity burden that aligned with the monitoring patterns. Already at this early stage of cHP, kidney function appears to be a key concern and may be important when considering therapeutic intervention. These data are consistent with our findings from a larger cHP population identified in the same database using a diagnosis-based approach.