Risk of Chronic Kidney Disease and Estimated Glomerular Filtration Rate Decline in Patients with Chronic Hypoparathyroidism: A Retrospective Cohort Study

INTRODUCTION: Chronic hypoparathyroidism, treated with conventional therapy of oral calcium supplements and active vitamin D, may increase the risk of kidney complications. This study examined risks of development and progression of chronic kidney disease (CKD) and estimated glomerular filtration rate (eGFR) decline in patients with chronic hypoparathyroidism. METHODS: A retrospective cohort study using a managed care claims database in the United States from January 2007 to June 2017 included patients with chronic hypoparathyroidism (excluding those receiving parathyroid hormone) and randomly selected patients without hypoparathyroidism followed for up to 5 years. Main outcome measures were (1) development of CKD, defined as new diagnosis of CKD stage 3 and higher or ≥ 2 eGFR measurements < 60 ml/min/1.73 m(2) ≥ 3 months apart, (2) progression of CKD, defined as increase in baseline CKD stage, (3) progression to end-stage kidney disease (ESKD), and (4) eGFR decline ≥ 30% from baseline. Time-to-event analyses included Kaplan-Meier analyses with log-rank tests, and both unadjusted and adjusted Cox proportional hazards models were used to compare outcomes between cohorts. RESULTS: The study included 8097 adults with and 40,485 without chronic hypoparathyroidism. In Kaplan-Meier analyses, patients with chronic hypoparathyroidism had higher risk of developing CKD and CKD progression and higher rates of eGFR decline (all P < 0.001). In multivariable Cox models adjusted for baseline characteristics, hazard ratios (95% confidence intervals [CIs]) were 2.91 (2.61–3.25) for developing CKD, 1.58 (1.23–2.01) for CKD stage progression, 2.14 (1.51–3.04) for progression to ESKD, and 2.56 (1.62–4.03) for eGFR decline (all P < 0.001) among patients with chronic hypoparathyroidism compared with those without hypoparathyroidism. CONCLUSION: Patients with chronic hypoparathyroidism have increased risk of development and progression of CKD and eGFR decline compared with those without hypoparathyroidism. Further studies are warranted to understand underlying mechanisms for the associations between chronic hypoparathyroidism and kidney disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12325-021-01658-1.