Usefulness of Serum Calcium in the Risk Stratification of Midterm Mortality among Patients with Acute Coronary Syndrome

Table 1

Characteristics of patients with acute myocardial infarction according to serum calcium quartiles.

Characteristics	Serum calcium concentration (mmol/l)				value
	Q1; <2.21	Q2; 2.21∼2.28	Q3; 2.28∼2.36	Q4; >2.36
Number of patients	645	648	648	653
Demographics
Age (years)	61.0 (53.0∼69.0)	61.0 (53.0∼68.0)	60.0 (53.0∼67.0)	59.0 (52.0∼66.0)	0.226
Men (n, %)	208 (32.2)	193 (29.8)	187 (28.9)	233 (35.7)	0.039
Current smoking (n, %)	306 (47.4)	321 (49.5)	312 (48.1)	319 (48.9)	0.889
Current alcohol use (n, %)	126 (19.5)	119 (18.4)	128 (19.8)	139 (21.3)	0.620
Medical history
Hypertension (n, %)	316 (49.0)	346 (53.4)	332 (51.2)	336 (51.5)	0.472
Diabetes mellitus (n, %)	135 (20.9)	131 (20.2)	141 (21.8)	163 (25.0)	0.172
Stroke (n, %)	88 (13.6)	115 (17.7)	91 (14.0)	90 (13.8)	0.113
CHD (n, %)	93 (14.4)	110 (17.0)	100 (15.4)	105 (16.1)	0.637
Previous PCI (n, %)	34 (5.3)	48 (7.4)	59 (9.1)	46 (7.0)	0.067
In-hospital complications
Acute heart failure (n, %)	125 (19.4)	111 (17.1)	115 (17.7)	90 (13.8)	0.054
Acute arrhythmia (n, %)	20 (3.1)	18 (2.8)	22 (3.4)	5 (0.8)	0.010
AV block (n, %)	41 (6.4)	43 (6.6)	34 (5.2)	34 (5.2)	0.585
Medication on admission
ACEI/ARB (n, %)	213 (33.0)	234 (36.1)	241 (37.2)	245 (37.5)	0.316
Beta-blocker (n, %)	364 (56.4)	381 (58.8)	376 (58.0)	390 (59.7)	0.670
Aspirin (n, %)	602 (93.3)	611 (94.3)	622 (96.0)	627 (96.0)	0.070
Statin (n, %)	563 (92.0)	576 (93.1)	588 (93.3)	604 (94.5)	0.359
Main diagnosis
STEMI (n, %)	385 (59.7)	386 (59.6)	359 (55.4)	327 (50.1)	0.001
NSTEMI/UA (n, %)	260 (40.3)	262 (40.4)	289 (44.6)	326 (49.9)
Reperfusion strategy
Coronary angiography (n, %)	495 (76.7)	493 (76.1)	479 (73.9)	497 (76.1)	0.657
PCI (n, %)	476 (76.5)	464 (74.2)	441 (70.9)	469 (73.6)	0.160
Thrombolysis (n, %)	35 (5.4)	34 (5.2)	35 (5.4)	21 (3.2)	0.178
Laboratory results
Hemoglobin (g/l)	140.2 (125.9∼152.2)	142.5 (130.6.∼154.5)	144.0 (133.0∼155.2)	144.7 (130.8∼156.8)	<0.001
Albumin (g/l)	41.2 (41.2∼43.9)	41.2 (40.2∼42.1)	41.2 (39.8∼41.8)	41.2 (39.2∼41.2)	<0.001
BUN (mmol/l)	5.5 (4.4∼6.8)	5.4 (4.4∼6.6)	5.5 (4.4∼6.6)	5.4 (4.4∼6.8)	0.027
Fasting glucose (mmol/l)	6.1 (5.2∼7.6)	5.9 (5.1∼7.7)	6.1 (5.2∼7.8)	6.0 (5.1∼8.0)	0.557
eGFR (ml/min/1.73 m^2)	104.1 (87.9∼114.0)	102.0 (86.5∼112.6)	102.3 (88.2∼111.9)	102.2 (85.1∼112.3)	0.877
Uric acid (μmol/l)	310.8 (255.2∼379.6)	329.7 (265.2∼387.3)	330.2 (274.8∼402.0)	332.4 (277.0∼396.4)	0.002
Serum phosphate (mmol/l)	1.1 (1.0∼1.3)	1.1 (1.0∼1.3)	1.2 (1.0∼1.3)	1.2 (1.1∼1.4)	0.011
Serum magnesium (mmol/l)	0.9 (0.8∼0.9)	0.9 (0.8∼0.9)	0.9 (0.8∼0.9)	0.9 (0.8∼0.9)	<0.001
Serum potassium (mmol/l)	4.1 (3.8∼4.3)	4.1 (3.9∼4.4)	4.2 (3.9∼4.5)	4.2 (3.9∼4.5)	0.220
Serum sodium (mmol/l)	139.8 (136.8∼142.5)	140.4 (137.8∼143.1)	141.1 (138.7∼143.6)	140.9 (138.4∼143.7)	<0.001
Serum chloride (mmol/l)	102.9 (100.3∼105.4)	103.3 (101.0∼105.5)	103.0 (101.2∼105.2)	102.7 (100.5∼105.0)	0.037
Echocardiography results
LVEF (%)	55.0 (47.0∼60.0)	54.0 (48.0∼60.0)	55.0 (48.0∼60.0)	56.0 (50.0∼64.0)	<0.001
LAD (mm)	37.0 (34.0∼39.0)	36.0 (34.0∼39.0)	37.0 (35.0∼39.0)	36.0 (34.0∼38.0)	<0.001
LVEDD (mm)	50.0 (47.0∼53.0)	49.0 (47.0∼53.0)	50.0 (47.0∼53.0)	49.0 (46.0∼52.0)	0.014
IVST (mm)	9.6 (9.0∼10.2)	9.6 (9.0∼10.3)	9.6 (9.0∼10.4)	9.8 (9.0∼10.7)	0.146
LVPW (mm)	9.6 (9.0∼10.2)	9.6 (9.0∼10.2)	9.6 (9.0∼10.2)	9.7 (9.0∼10.4)	0.340

ACEI, angiotensin-converting enzyme inhibitors; ARB, angiotensin receptor blockers; BUN, blood urea nitrogen; CHD, coronary heart disease; eGFR, estimated glomerular filtration rate; IVST, interventricular septum thickness; LAD, left atrial diameter; LVEDD, left ventricular end diastolic diameter; LVEF, left ventricular ejection fraction; LVPW, left ventricular posterior wall thickness; NSTEMI, non-ST-segment elevation myocardial infarction; PCI, percutaneous coronary intervention; and STEMI, ST-segment elevation myocardial infarction. Data are expressed as the mean (standard deviation) for normally distributed data, the median (interquartile range) for nonnormally distributed data, and the percentage (%) for categorical variables.