Serum Anion Gap Is Associated with All-Cause Mortality among Critically Ill Patients with Congestive Heart Failure

Table 3

HRs (95% CIs) for all-cause mortality across groups of serum anion gap.

Variable	Crude		Model I		Model II
	HR (95%CIs)	value	HR (95%CIs)	value	HR (95%CIs)	value
30-day all-cause mortality
Anion gap	1.10 (1.09, 1.11)	<0.0001	1.11 (1.10, 1.12)	<0.0001	1.05 (1.03, 1.07)	<0.0001
Anion gap (tertile)
<13	1 (ref)		1 (ref)		1 (ref)
≥13, <16	1.50 (1.28, 1.75)	<0.0001	1.47 (1.25, 1.72)	<0.0001	1.28 (1.09, 1.50)	0.0031
≥16	2.63 (2.27, 3.03)	<0.0001	2.62 (2.27, 3.03)	<0.0001	1.74 (1.46, 2.08)	<0.0001
for trend	<0.0001		<0.0001		<0.0001
Anion gap (quartile)
<12	1 (ref)		1 (ref)		1 (ref)
≥12, <14	1.41 (1.15, 1.73)	0.0009	1.39 (1.13, 1.70)	0.0016	1.22 (0.99, 1.49)	0.0621
≥14, <17	1.80 (1.50, 2.17)	<0.0001	1.75 (1.46, 2.11)	<0.0001	1.53 (1.26, 1.86)	<0.0001
≥17	3.16 (2.65, 3.78)	<0.0001	3.20 (2.68, 3.82)	<0.0001	1.97 (1.59, 2.45)	<0.0001
for trend	<0.0001		<0.0001		<0.0001
90-day all-cause mortality
Anion gap	1.09 (1.07, 1.10)	<0.0001	1.09 (1.08, 1.10)	<0.0001	1.04 (1.02, 1.06)	<0.0001
Anion gap (tertile)
<13	1 (ref)		1 (ref)		1 (ref)
≥13, <16	1.36 (1.20, 1.54)	<0.0001	1.33 (1.17, 1.51)	<0.0001	1.17 (1.03, 1.34)	0.0170
≥16	2.22 (1.98, 2.50)	<0.0001	2.23 (1.98, 2.51)	<0.0001	1.53 (1.32, 1.77)	<0.0001
for trend	<0.0001		<0.0001		<0.0001
Anion gap (quartile)
<12	1 (ref)		1 (ref)		1 (ref)
≥12, <14	1.33 (1.14, 1.56)	0.0004	1.31 (1.12, 1.54)	0.0008	1.17 (0.99, 1.37)	0.0637
≥14, <17	1.57 (1.35, 1.82)	<0.0001	1.53 (1.32, 1.77)	<0.0001	1.35 (1.15, 1.57)	<0.0001
≥17	2.57 (2.23, 2.97)	<0.0001	2.62 (2.27, 3.02)	<0.0001	1.66 (1.39, 1.98)	<0.0001
for trend	<0.0001		<0.0001		<0.0001

Models were derived from Cox proportional hazards regression models. Crude model adjusted for none. Model I adjusted for age, gender, and ethnicity. Model II adjusted for age, gender, ethnicity, temperature, systolic blood pressure, diastolic blood pressure, respiratory rate, heart rate, percutaneous oxygen saturation, weight, atrial fibrillation, liver disease, valvular heart diseases, pulmonary circulation diseases, pneumonia, respiratory failure, diabetes, stroke, malignancy, lactate, prothrombin time, white blood cell, blood urea nitrogen, creatinine, potassium, bicarbonate, glucose, vasopressor, dialysis, mechanical ventilation, SOFA, SAPSII, and NT-proBNP. Note: HR: hazard ratio; CI: confidence interval; SOFA: stroke, and malignancy. Calculate the sequential organ failure assessment score; SAPSII: simplified acute physiology score II; NT-proBNP: N-terminal probrain natriuretic peptide.