Poster Presentation 29th Australian and New Zealand Bone and Mineral Society Annual Scientific Meeting 2019

Causes of inpatient hypercalcaemia in modern tertiary hospital care (#143)

Senthil Thillainadesan 1 2 , Stephen Twigg 1 2 , Nimalie Perera 1
  1. Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
  2. University of Sydney, Camperdown, NSW, Australia

Hypercalcaemia occurs in about 1% of hospital inpatients. Studies published >20years ago identified malignancy and primary hyperparathyroidism as the most common causes(1–3). We aimed to determine if there has been any change to the prevalence or causes of inpatient hypercalcaemia given recent changes to diagnostic methods and treatments in a quaternary teaching hospital.

Method: A retrospective study of inpatients admitted from January 2017-2018 was conducted. Patients with ≥2 corrected calcium levels >2.70mmol/L were identified on review of pathology database. Medical records were reviewed to determine the cause of hypercalcaemia and treatment.  

Results:   Hypercalcaemia occurred in 336 hospital admissions involving 292 unique patients. This represents 1.2% of all admissions during this 12 month period. Hypercalcaemia was mild (<3.0mmol/L) in 85% of admissions, moderate(3-3.5mmol/L) in 12% and severe(>3.5mmol/L) in 3%.

In 78/292(27%) patients hypercalcaemia occurred whilst admitted to the intensive care unit (ICU) and the cause of hypercalcaemia was not identified but was associated with mortality (31/78) or resolved following treatment of the underlying condition. In 54/292(18%) non-ICU patients hypercalcaemia improved following hydration or treatment of underlying illness. 

In the remaining 157/292(54%) non-ICU patients with persistent hypercalcaemia,  41(26%) were due to malignancy, 40(25%) primary hyperparathyroidism and 19(12%) hyperparathyroidism in the setting of chronic kidney disease. Other causes included immobility, liver disease and iatrogenic.

Pharmacological treatment to lower calcium was used in 45/292 (15%) patients, with IV bisphosphonates used in 32(11%), denosumab in 6(2%) and salcalcitonin in 3(1%). 

Conclusion: The prevalence (1.2%) and causes of inpatient hypercalcaemia has remained unchanged over many years,with most common causes being malignancy and primary hyperparathyroidism. A high proportion of hypercalcaemia occurred in ICU and was associated with high mortality. The significance and mechanism of ICU hypercalcaemia needs further investigation. 

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Figure 1 Causes of persistent hypercalcaemia in 157 patients

 

  1. Fisken RA, Heath DA, Somers S, Bold AM. Hypercalcaemia in hospital patients. Clinical and diagnostic aspects. Lancet. 1981 Jan 24;1(8213):202–7.
  2. Arimott RD, Melick RA. Hypercalcaemia in an Adult Hospital Population: Comparison of Inpatients of 1966 with those of 1976. Med J Aust . 1979.
  3. Shek CC, Natkunam A, Tsang V, Cockram CS, Swaminathan R. Incidence, causes and mechanism of hypercalcaemia in a hospital population in Hong Kong. Q J Med. 1990 Dec;77(284):1277–85.