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

Figures & data

Table 1 Baseline Characteristics of Patients (n=1008)*

Characteristics	CHUL (n = 476)	HDQ (n = 532)	Total (N = 1008)
Age (mean, SD)	60.3 (23.2)	70.0 (15.2)	65.4 (19.9)
Female	289 (60.7)	252 (47.4)	541 (53.7)
Comorbidities
Coronary artery disease	72 (15.2)	177 (33.3)	249 (24.8)
Diabetes type 1 or 2	85 (17.9)	151 (28.4)	236 (23.5)
Neoplasia	74 (15.6)	254 (47.8)	328 (32.6)
Metastasis	7 (1.5)	85 (16.0)	92 (9.1)
Endocrine disease^a	104 (21.9)	133 (25.0)	237 (23.6)
Chronic renal failure	78 (16.4)	164 (30.9)	242 (24.1)
Chronic obstructive	40 (8.4)	96 (18.1)	136 (13.5)
pulmonary disease
Rheumatic disease^b	24 (5.1)	21 (4.0)	45 (4.5)
Malnutrition	7 (1.5)	11 (2.1)	18 (1.8)
Charlson index
0–1	185 (38.5)	42 (7.9)	227 (22.5)
2–4	117 (24.6)	120 (22.6)	237 (23.5)
5+	174 (36.6)	370 (69.5)	544 (54.0)
Medication
Proton pump inhibitor	161 (34.0)	290 (54.7)	451 (44.9)
Vitamin D supplements	139 (29.3)	242 (45.7)	381 (37.9)
Other vitamins	67 (14.1)	78 (14.7)	145 (14.4)
Calcium supplements	104 (22.0)	199 (37.5)	303 (30.2)
Furosemide	50 (10.5)	104 (19.6)	154 (15.3)
Hydrochlorothiazide	28(5.9)	50 (9.4)	78 (7.8)
Other diuretics^c	5 (1.1)	20 (3.8)	25 (2.5)
Phosphate-binders^d	0 (0)	20 (3.8)	20 (2.1)
Alcohol abuse^e	63 (13.3)	65 (12.1)	128 (12.7)

Notes: *All data are presented as N (%), unless otherwise specified. ^aEndocrine disease: hypo-hyperthyroidism, hypo-hyperparathyroidism, adrenal insufficiency, Cushing disease, Addison disease, multiple endocrine neoplasia (MEN), pheochromocytoma. Diabetes mellitus not included. ^bRheumatic diseases: Rheumatic disease (eg, rheumatoid arthritis, polymyalgia rheumatica) or connective tissue disorder (eg, Lupus, Sjogren syndrome, erythrodermia, other connectivitis). ^cOther diuretics: potassium sparing (eg, spironolactone, eplerone, amiloride, triamterene) and acetazolamide. ^dPhosphate-binders or Phosphate-scavengers: Sevelamer (Renvela, Renagel) and others. ^eAlcohol abuse: known alcoholism or >3 drinks per day on a regular basis.

Table 2 Prevalence of Abnormal Calcium, Magnesium and Phosphorus Serum Level*

	CHUL	HDQ	Total
Hypercalcemia	4.7 (3.0–7.2)	2.9 (1.7–4.9)	3.8 (2.7–5.2)
Hypocalcemia	9.9 (7.4–13.0)	18.0 (14.8–21.6)	14.1 (12.1–16.5)
Hypermagnesemia	4.6 (2.9–7.1)	7.0 (5.0–9.6)	5.9 (4.5–7.6)
Hypomagnesemia	12.5 (9.7–15.9)	21.4 (18.0–25.2)	17.2 (14.9–19.7)
Hyperphosphatemia	6.0 (4.1–8.7)	12.3 (9.7–15.6)	9.3 (7.6–11.4)
Hypophosphatemia	11.3 (8.6–14.7)	11.9 (9.3–15.2)	11.6 (9.7–13.9)

Note: *All data are presented as % (95% confidence interval).

Table 3 Most Frequent Presenting Complaints* and Signs in Patients Who Had a Calcium, Magnesium or Phosphorus Serum Level Measurement

	n (%)
● Neurologic^a	656 (65.1)
Weakness	356 (35.3)
Altered mental status	215 (21.3)
Headache	125 (12.4)
Gait disturbance	97 (9.6)
Paresthesia	81 (8.0)
Seizure	47 (4.7)
Tremors	44 (4.4)
● Gastro-intestinal	477 (47.3)
Nausea/Vomiting	213 (21.1)
Abdominal pain	211 (20.9)
Anorexia	193 (19.1)
Constipation	46 (4.6)
Diarrhea	28 (2.8)
● Cardiovascular	205 (20.3)
Poor peripheral perfusion	80 (7.9)
Palpitations	73 (7.2)
Syncope/pre-syncope	66 (6.5)
Increased work of breathing or desaturation	62 (6.2)
● Musculoskeletal	232 (23.0)
Non specific musculoskeletal pain	213 (21.1)
Bone pain	41 (4.1)
● Miscellaneous
Weight loss	72 (7.2)
Fever	34 (3.4)
Depressive symptoms	29 (2.9)
Hallucinations	29 (2.9)

Notes: *Based on the Canadian Emergency Department Information Systems presenting complaint list. ^aCategories are not mutually exclusive.

Table 4 Protective and Risk Factors of Abnormal Calcium, Magnesium and Phosphorus Serum Level in the Emergency Department^a

Abnormality	Risk Factors	Adjusted OR (95% CI)
Hypocalcemia	Respiratory distress	3.3 (1.6–6.7)
	Diuretics (other than furosemide and hydrochlorothiazide)	3.2 (1.3–8.4)
	Hyperphosphatemia	3.0 (1.6–5.6)
	Hypomagnesemia	2.6 (1.6–4.2)
	Anti-neoplastic medication	2.3 (1.3–4.1)
	Long QTc	2.0 (1.2–3.3)
	Chronic kidney disease	2.0 (1.2–3.1)
	Alcohol abuse	2.0 (1.1–3.4)
	Abdominal pain	1.9 (1.2–3.1)
	Hypophosphatemia	1.9 (1.1–3.3)
	Hypermagnesemia	0.3 (0.1–0.9)
Hypercalcemia	Bone pain	5.7 (2.0–15.8)
	Hyperphosphatemia	4.6 (1.8–11.6)
	Vitamin D	4.1 (2.0–8.6)
	Hallucinations	3.9 (1.2–13.1)
	Furosemide	0.1 (0.0–0.8)
Hypomagnesemia	Diabetes	2.7 (1.8–3.9)
	Hypocalcemia	2.3 (1.5–3.7)
	Corticosteroids	2.2 (1.3–3.7)
	Hypophosphatemia	1.8 (1.1–3.0)
	Nausea	1.8 (1.2–2.7)
	Calcium intake	1.6 (1.1–2.4)
Hypermagnesemia	Hyperphosphatemia	5.9 (2.8–12.4)
	Poor extremity perfusion	4.3 (1.6–11.3)
	Chronic kidney disease	3.0 (1.4–6.3)
	Furosemide	2.9 (1.3–6.4)
	Hypocalcemia	0.2 (0.0–0.5)
Hypophosphatemia	Seizure	4.0 (1.8–8.6)
	Hypocalcemia	2.5 (1.5–4.3)
	Hypomagnesemia	2.0 (1.2–3.2)
	Female	0.6 (0.4–0.9)
Hyperphosphatemia	Phosphate-binders	4.8 (1.4–15.9)
	Hypermagnesemia	4.5 (2.1–9.5)
	Hypercalcemia	4.2 (1.5–11.4)
	Chronic kidney disease	4.1 (2.2–7.7)
	Hypocalcemia	2.4 (1.2–4.6)
	Peripheral vascular atherosclerotic disease	2.2 (1.1–4.6)
	Abdominal pain	1.9 (1.1–3.4)
	Age^b	0.98 (0.96–0.99)

Notes: ^aStatistically significant associations identified with stepwise selection algorithm of logistic regression model, p value < 0.05. Predictive risk factors OR > 1/Protective effect in italic, OR < 1. ^bContinuous variable.

Table 5 Protective and Risk Factors of Corrective Interventions for Any Calcium, Magnesium or Phosphorus Abnormality^a

Risk Factors	OR (95% CI)
Calcimimetics	10.8 (1.8–64.6)
Calcium intake	2.7 (1.6–4.5)
Poor peripheral perfusion	2.5 (1.3–4.9)
COPD	2.0 (1.1–3.6)
Nausea	1.9 (1.1–3.2)

Notes: Statistically significant associations identified with stepwise selection algorithm of logistic regression model, p value < 0.05. Predictive risk factors OR > 1/Protective effect in italic, OR < 1.