Clinical characteristics and short-term outcomes of calcium ion disorders in patients with oncologic emergencies

Data on serum calcium abnormalities in oncology emergency settings remain limited. This study aimed to investigate their prevalence, clinical characteristics, associated factors, and 28-day outcomes among patients presenting to a specialized oncology emergency department. This retrospective study included 8,018 unique patients who presented to the Oncology Emergency Department of the Cancer Hospital, Chinese Academy of Medical Sciences, between February and June 2023. Clinical characteristics and 28-day outcomes were compared between patients with serum calcium abnormalities and those with normocalcemia. Multivariable logistic regression was used to identify factors associated with serum calcium abnormalities. Serum calcium abnormalities were identified in 424 patients (5.3%), including 365 with hypocalcemia (4.6%) and 59 with hypercalcemia (0.7%). Grade 1 abnormalities accounted for 57.0% of patients with hypocalcemia and 86.4% of patients with hypercalcemia. In the unadjusted analysis, the 28-day deterioration rate was higher among patients with hypocalcemia than among those with normocalcemia (12.6% vs. 4.3%), whereas the rate did not differ significantly between patients with hypercalcemia and normocalcemia (6.8% vs. 4.3%). Twenty-eight-day outcomes did not differ significantly between Grade 1 and Grade ≥ 2 hypocalcemia or hypercalcemia. In the multivariable analyses, hypercalcemia was associated with female sex, age > 65 years, hypokalemia, hyponatremia, and renal dysfunction. Hypocalcemia was associated with female sex, Eastern Cooperative Oncology Group performance status 2–4, bone metastasis, hypoalbuminemia, renal dysfunction, hyponatremia, and anemia. Serum calcium abnormalities occurred in approximately 5% of patients presenting with oncologic emergencies, with hypocalcemia more common than hypercalcemia. Hypocalcemia was associated with several indicators of poorer clinical condition and a higher unadjusted 28-day deterioration rate. Short-term outcomes did not differ significantly between Grade 1 and Grade ≥ 2 calcium abnormalities.