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Abstract: SA-PO208

Hypercalciuria and Risk for Hypercalcemia Among Veterans With Urinary Stone Disease

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Ganesan, Calyani, Stanford University School of Medicine, Stanford, California, United States
  • Thomas, I-Chun, VA Palo Alto Health Care System, Palo Alto, California, United States
  • Seib, Carolyn Dacey, Stanford University School of Medicine, Stanford, California, United States
  • Conti, Simon, Stanford University School of Medicine, Stanford, California, United States
  • Leppert, John, Stanford University School of Medicine, Stanford, California, United States
  • Pao, Alan C., Stanford University School of Medicine, Stanford, California, United States
Background

Approximately 70-80% of patients with urinary stone disease form calcium-based stones. The most common abnormality detected in the urine of these patients is hypercalciuria. At the time of their stone diagnosis and urine calcium measurement, most patients have a normal serum calcium concentration. It remains unknown whether the level of urine calcium excretion associates with higher risk for developing hypercalcemia.

Methods

We used national Veterans Health Administration data to define patients with urinary stone disease as those with one or more inpatient or two or more outpatient encounters for urinary stone disease or one or more stone procedures between 2007 and 2019. We then selected patients who had a 24-hour urine measurement within 6 months of their stone diagnosis. We defined normocalcemia as a measured or albumin-corrected serum calcium measurement < 10.2 mg/dL. We defined the primary outcome hypercalcemia as a measured or albumin-corrected serum calcium measurement > 10.2 mg/dL. We performed Cox proportional hazards regression to identify the risk of developing hypercalcemia by level of 24-hour urine calcium excretion.

Results

We identified 11,926 Veterans with urinary stone disease, normocalcemia, and a 24-hour urine calcium measurement. Within this cohort 23.8% (2841 individuals) had an elevated 24-hour urine calcium measurement >200mg/day and 4.6% (546 individuals) developed hypercalcemia. We found that level of 24-hour urine calcium excretion did not associate with risk of developing hypercalcemia.

Conclusion

Patients with urinary stone disease and normal serum calcium concentration are not at higher risk for developing hypercalcemia even if they have higher levels of 24-hour urine calcium excretion. Therefore, initial treatment should be aimed at correcting urinary risk factors. Further research is needed to clarify the utility of PTH measurement to guide further evaluation and surveillance in this population.

Funding

  • NIDDK Support