Hypercalcaemia: an elevated PTH-related protein helped diagnose malignancy

Clinical bottom line (level 4)

  1. An elevated PTH-related protein made malignancy much more likely, but a normal level did not exclude it.
  2. A normal PTH level made primary hyperparathyroidism very unlikely. Further tests were required if an elevated level was found.
  3. Half of patients with hypercalcaemia had malignancy, and a sixth had primary hyperparathyroidism.
Lee et al: Journal of Endocrinological Investigation 1997; 20: 404-409
Expires November 2004

The study

Setting: 2 acute hospitals, China

178 patients (aged 25 to 89; mean 64, 74% male) with hypercalcaemia (corrected calcium > 2.74 mmol/l)

Independent ?blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:
  • Specific cause
    • malignancy: bony metastases: hot spots on bone scanning or bone lesions on radiological examination
    • hyperparathyroidism: elevated intact parathormone level and no other cause, or pathological proof after parathyroidectomy
Diagnostic test:
  • parathyroid hormone level
  • PTH related protein level

The evidence

pre-test probability of malignancy: 52%, (95% CI: 45% to 60%)
pre-test probability of primary hyperparathyroidism: 16%, (95% CI: 10% to 21%)

diagnostic test hyperparathyroidism no hyperparathyroidism LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
elevated PTH 28 18 8.3
(5.4 to 13) 		61% 0.0
(0.0 to 0.12) 		0%
total 28 150


diagnostic test malignancy no malignancy LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
elevated PTHrP 71 5 13
(5.5 to 31) 		93% 0.25
(0.17 to 0.36) 		22%
total 93 85

Comments


Citation

  1. Lee J-K, Chuang M-J, Lu C-C, et al: Parathyroid hormone and parathyroid hormone related protein assays in the investigation of hypercalcemic patients in hospital in a Chinese population. Journal of Endocrinological Investigation 1997; 20: 404-409
Search Terms: ?
Contributor: Chris Ball and Musab Hayatli, November 1999
Reviewer:

Clinical Question.
Patient hypercalcaemia hypercalcemia
Intervention or Exposure parathyroid hormone, PTH-related protein
Outcome malignancy, primary hypercalcaemia