AT THE ACADEMIC SURGICAL CONGRESS
LAS VEGAS (FRONTLINE MEDICAL NEWS) – A triad of signs – elevated serum calcium, elevated parathyroid hormone, and a history of kidney stones – can predict hypercalcemic crisis among patients with hyperparathyroidism, a study showed.
Patients who present with the trifecta should be considered for expedited parathyroidectomy, Andrew Lowell said at the Association for Academic Surgery/Society of University Surgeons Academic Surgical Congress.
“We were able to develsop a decision tree that providers can use to determine if a patient falls into that risk category and whether to expedite the surgery,” said Mr. Lowell, a medical student at the University of Wisconsin, Madison.
The model was based on a retrospective analysis of 183 patients with hyperparathyroidism who were hospitalized and treated for hypercalcemia. These were divided into two groups: those who developed a hypercalcemic crisis (29) and those who did not (154).
There were no significant differences in age, sex, alcohol or tobacco use, body mass index, or Charlson comorbidity score. However, those who developed a crisis were significantly more likely to have had kidney stones (31% vs. 14%). Their preoperative serum calcium level was also significantly higher (median, 13.8 vs. 12.4 mg/dL), and they had significantly higher parathyroid hormone (PTH) levels (median, 318 vs. 160 pg/mL). Their preoperative vitamin D level was also significantly lower (median, 16 vs. 26 ng/mL).
Parathyroidectomy was equally effective in both groups, but twice as many patients with crisis needed a multigland resection (24% vs. 12%).
Mr. Lowell conducted a univariate, and then a multivariate, analysis to determine independent risk factors for hypercalcemic crisis. This revealed that a higher preoperative calcium level, an elevated PTH level, and a history of kidney stones were significantly associated with crisis.
Hypercalcemia developed in:
• 91% of those with a serum calcium higher than 13.25 mg/dL and 6% of those with a lower serum calcium level.
• 60% of those with a PTH of 394 pg/mL or higher and 19% of those with a PTH less than 394 pg/mL.
• 31% of those with a history of kidney stones and 14% of those without such a history.
The investigators created a decision tree that begins with a calcium level greater than 13.25 mg/dL, a PTH level higher than 394 pg/mL, and a Charlson comorbidity index of 4 or greater. The model carried an overall predictive accuracy of 90% and a positive predictive value of 76%, Mr. Lowell said.
Session moderator Benjamin Poulose, MD, of Vanderbilt University, Nashville, Tenn., said the model looks very good on paper, but might be challenging to implement when assessing emergent patients.
Mr. Lowell suggested that it would be better employed in an outpatient setting.
“I think this would be more useful in the situation of a physician who knows that patient’s comorbidities, in the context of counseling, to determine” the need for and timing of surgery, he said.
He had no relevant financial disclosures.
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