Kidney Week

Abstract: TH-PO132

Parathyroid Axis Irregularities in Patients with Hyperaldosteronism

Session Information

• CKD-MBD: Clinical
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 502 Bone and Mineral Metabolism: Clinical

Authors

• Dweik, Loai, Cleveland Clinic Akron General, Akron, Ohio, United States

Loai Dweik, MD

• Salih Bacha, Dania, Cleveland Clinic, Cleveland, Ohio, United States

Dania Salih Bacha, MD

• Mendpara, Vaidehi A., Cleveland Clinic, Cleveland, Ohio, United States

Vaidehi A. Mendpara, MBBS

• Xiao, Huijun, Cleveland Clinic, Cleveland, Ohio, United States

Huijun Xiao, MS

• Thomas, George, Cleveland Clinic, Cleveland, Ohio, United States

George Thomas, MD, FASN

• Rao, Pratibha Pr, Cleveland Clinic, Cleveland, Ohio, United States

Pratibha Pr Rao, MD, MPH

• Nakhoul, Georges, Cleveland Clinic, Cleveland, Ohio, United States

Georges Nakhoul, MD, MEd, FASN

• Taliercio, Jonathan J., Cleveland Clinic, Cleveland, Ohio, United States

Jonathan J. Taliercio, DO, FASN

• Bassil, Elias, Cleveland Clinic, Cleveland, Ohio, United States

Elias Bassil, MD, PharmD

• Mehdi, Ali, Cleveland Clinic, Cleveland, Ohio, United States

Ali Mehdi, MD, MEd, FASN

Background

Patients with hyperparathyroidism (HPT) have increased cardiovascular risks. A bi-directional relationship between the renin-aldosterone axis and the parathyroid-calcium (PTH-Ca) axis has been proposed whereby PTH and aldosterone can activate one another and exacerbate vascular damage. This study aims to investigate the prevalence of PTH-Ca axis abnormalities in patients with primary aldosteronism (PA).

Methods

In this retrospective review, patients 18 years or older with PA who had PTH levels measured between 2018 and 2023 were included. Patients with secondary HPT were excluded. The prevalence of HPT, hypercalcemia (HyperCa), and hypophosphatemia (HypoP) was calculated.

Results

164 patients were identified. Median age was 70 years and 44% were female. Primary HPT was prevalent in 13% of the cohort. HyperCa (Ca > 10.2 mg/dL on 2 occasions) and HypoP (P<2.5 mg/dL on 2 occasions) were observed in 32% and 33% of patients respectively. After excluding patients on Calcium, vitamin D supplements, or thiazides, 24% of the remaining 66 patients had HyperCa. Among patients with HyperCa and/or HypoP (N=83), median interquartile range (IQR) PTH was 59.5 pg/mL (41.0 – 88.8), median (IQR) 24-hour urinary Ca:166.5 mg/day (77.9 – 257.6), and 22% had nephrolithiasis. We then excluded patients with a diagnosis of primary HPT from this sub-cohort and were left with 65 patients. The median (IQR) PTH was unsuppressed at 47.0 pg/mL (38.0 – 79.5), median (IQR) 24-hour urinary Ca: 144.0 mg/day (101.4 – 221.7), and 24% had nephrolithiasis.

Conclusion

In a cohort of PA patients, the prevalence of PTH-Ca abnormalities is quite high. Primary HPT was seen in 13% of patients as compared to <1% in the general population. HyperCa was also seen in a third of patients, many folds higher than the general population (1-2%). This remained true even after excluding those on medications that can raise serum Ca. Looking at patients with HyperCa and/or HypoP and excluding those with primary HPT, the biochemical profile (unsuppressed PTH and 24 urine Ca) suggested undiagnosed primary HPT. True primary HPT is likely more prevalent in this population. Further studies are needed to better understand this interaction and therapeutic implications.