Identification of Predictors of Abnormal Calcium, Magnesium and Phosphorus Blood Levels in the Emergency Department: A Retrospective Cohort Study

Abstract

Purpose: With rising healthcare costs limiting access to care, the judicious use of diagnostic tests has become a critical issue for many jurisdictions. Calcium, magnesium and phosphorus serum levels are regularly performed tests in the emergency department, but their clinical relevance have come into question. Authors sought to determine risk factors that could predict abnormal calcium, magnesium and phosphorus serum levels, as well as identify patients who may need corrective interventions. Methods: A retrospective cohort study was conducted in two academic hospitals in Québec City. Demographic and clinical characteristics of 1008 patients who had serum calcium and/ or magnesium and/or phosphorus levels drawn by an emergency physician were collected. Multivariate logistic regression models were fitted to obtain adjusted odds ratios for each risk factor for abnormal calcium or magnesium or phosphorus blood levels, and for a required intervention. Results: Among patients for whom calcium, magnesium and phosphorus were tested in the Emergency Department, the most significant risk factors (OR>2) for electrolytic abnormality were as follows: hypocalcemia -respiratory distress, diuretics (excluding loop and thiazide), anti-neoplastic medication, long QTc, chronic kidney disease (CKD); hypercalcemia -bone pain, vitamin D, hallucinations; hypomagnesemia -diabetes, corticosteroids; hypermagnesemia -poor extremity perfusion, CKD, furosemide; hypophosphatemia -seizure; hyperphosphatemia -phosphate-binders, CKD, peripheral vascular atherosclerotic disease. Of all patients tested, 3.4% received a corrective intervention initiated by the emergency physician. Predictors of intervention on an electrolyte abnormality include poor peripheral perfusion, nausea and chronic obstructive pulmonary disease (COPD). Conclusion: Emergency physicians can potentially reduce the unnecessary testing of calcium, magnesium and phosphorus blood levels by targeting patients with high-acuity conditions or chronic comorbidities such as CKD, diabetes and COPD.

Ionized Magnesium: Interpretation and Interest in Atrial Fibrillation

“…Among ED patients, the 6.9% incidence of hypo-iMg is lower than in the literature. An Australian study showed a 10% of abnormal (hypo and hyper) serum Mg level [ 39 ] and a recent study based on 1008 patients found a 17.2% rate of hypomagnesemia [ 40 ]. When using the ranges determined in our study, the 9.2% incidence of hypo-iMg seems more relevant especially since it is significantly higher than in the control group.…”

Alterations of Serum Magnesium Concentration in Animal Models of Seizures and Epilepsy—The Effects of Treatment with a GPR39 Agonist and Knockout of the Gpr39 Gene

“…Variants of the TRPM6 gene-another TRP channel belonging to subfamily M, which is a close homolog of TRPM7 [31]-caused hypomagnesaemia accompanied by seizures [32]. Two recent studies did not find seizures as a significant risk factor for hypomagnesaemia [33,34], but seizures are among the neurological symptoms that may occur in those with severe hypomagnesaemia [35,36]. A meta-analysis of 40 studies showed that the serum magnesium concentrations were not different between epilepsy patients and control subjects, but hair magnesium concentrations were lower in both treated and non-treated patients compared to controls.…”