End-Organ Damage Associated With Primary Hyperparathyroidism.

IMPORTANCE

Primary hyperparathyroidism (PHPT) is common and contributes to skeletal and kidney end-organ damage. Although parathyroidectomy can mitigate these complications, many patients are managed with observation, and real-world data on the population-based frequency and timing of end-organ damage under usual care are limited.

OBJECTIVE

To evaluate the frequency and timing of end-organ damage associated with PHPT.

DESIGN, SETTING, AND

PARTICIPANTS

This cohort study included a population-based cohort identified from national electronic health record (EHR) and claims data (2010-2023) with follow-up through 2023. Participants were adults with a new biochemical diagnosis of PHPT. Data analysis was performed from August 2025 to April 2026.

EXPOSURE: A new biochemical diagnosis of PHPT was defined as an elevated PTH (>65 pg/mL) within 1 month after a second elevated calcium level (serum calcium >10.2 mg/dL or ionized calcium >1.3 mmol/L or >5.3 mg/dL).

MAIN OUTCOMES AND MEASURES: PHPT-associated end-organ damage (osteoporosis, atraumatic fractures, kidney stones, stage 3 or worse chronic kidney disease) at or after PHPT diagnosis using EHR or claim codes and laboratory data, in addition to the frequency and timing of parathyroidectomy.

RESULTS

A total of 43 399 patients with PHPT were identified (mean [SD] age, 67.9 [12.5] years; 33 854 [78%] female and 9545 [22%] male), of whom 22 279 (51.3%) had end-organ damage at diagnosis. Among 21 120 patients without end-organ damage at diagnosis, 6762 (32.0%) progressed to end-organ damage after a median (IQR) 516 (166-1125) days. Only 4442 patients (19.9%) with end-organ damage at diagnosis were treated with parathyroidectomy. Among those who progressed to end-organ damage, 1348 (19.9%) underwent subsequent parathyroidectomy, which occurred a median (IQR) 154 (41-439) days later.

CONCLUSIONS AND RELEVANCE: In this national cohort of adults with a biochemical diagnosis of PHPT, 67% had PHPT-associated end-organ damage at diagnosis or on follow-up. Despite this, parathyroidectomy was uncommon. These findings may inform strategies to optimize utilization of parathyroidectomy and mitigate PHPT-associated morbidity.