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Kidney Week

Abstract: FR-PO243

Immobilization-Associated Hypercalcemia in Patients with Malignancy in the Hospital Setting: A Cohort Study

Session Information

Category: Onconephrology

  • 1700 Onconephrology


  • Kanduri, Swetha Rani, Ochsner Medical Center, New Orleans, Louisiana, United States
  • Stark, Ana Isabel, Ochsner Medical Center, New Orleans, Louisiana, United States
  • Smith, Alexander M., Ochsner Medical Center, New Orleans, Louisiana, United States
  • Lam, Walter, Ochsner Medical Center, New Orleans, Louisiana, United States
  • Velez, Juan Carlos Q., Ochsner Medical Center, New Orleans, Louisiana, United States

Malignancy-associated hypercalcemia (MAH) is not uncommon in patients with cancer. Direct bone invasion (primary bone cancer, bone metastasis, multiple myeloma) and humoral hypercalcemia (elevated PTH, PTH-related peptide (PTHrP) and calcitriol) are the predominant etiologies. Although a significant proportion of patients with malignancy have poor functional status, immobilization-associated hypercalcemia (Immob-HCa) is not well recognized in this population. We examined the relative contribution of Immob-HCa to all causes of MAH in the hospital setting.


A retrospective review of medical records was conducted searching for cases of MAH over a 3-year period. Hypercalcemia was defined as serum calcium >11.0 mg/dL. Definite Immob-HCa was defined as presence of immobility >1 week prior to admission or ECOG score >4, needing complete assistance, combined with absence of disqualifying laboratory data (PTH >60 ng/dL, 1,25 vitamin D >70 pg/mL, 25 vitamin D >80 ng/mL, PTHrP >2.5 pmol/L) monoclonal gammopathy, lytic lesion by imaging or alternative etiology (sarcoidosis, exposure to thiazide, or calcium or vitamin D supplementation). Probable Immob-HCa was defined as documented immobility and absence of alternative etiology, but incomplete laboratory data.


A total of 145 patients with in-hospital MAH were identified. The median age was 68 (33-92), 45% women, 64% white, 31% self-identified black; median peak serum calcium was 12.1 (11.2-17.8) mg/dL. High ionized calcium was verified in 41 (28%) cases. 74 (51%) had evidence of bone metastasis (including primary bone cancer), multiple myeloma accounted for 7 (5%) cases, elevated PTH for 10 (7%) cases, PTHrP for 11 (7%) and elevated calcitriol for 3 (2%) cases. One case was categorized as Definite Immob-HCa and 4 cases as Probable Immob-HCa. The etiology of MAH was undetermined in 35 (24%) cases. Thus, Immob-HCa accounted for up to 4% (5/145) of in-hospital MAH. Concomitant acute kidney injury (AKI) was present in 3 out of 5 (60%) cases of Immob-HCa.


Immob-HCa accounted for approximately 1 in 29 of cases of in-hospital MAH and is accompanied by AKI in about half of the cases. Notably, incomplete diagnostic work up for MAH was common and may underestimate the incidence of Immob-HCa.