The ability of NT-proBNP to detect chronic heart failure and predict all-cause mortality is higher in elderly Chinese coronary artery disease patients with chronic kidney disease

Figures & data

Table 1 Baseline characteristics of study population

Variables	No CKD (n = 641)	CKD (n = 358)		Total (n = 999)
		eGFR 45–60 mL/minute/1.73 m^2 (n = 194)	eGFR < 45 mL/minute/1.73 m^2 (n = 164)
Demographics
Age (years) median (75% range)	85 (81–89)	86 (83–90)	87 (82–91)	86 (82–90)
Males (%)	592 (92.4)	172 (88.7)	140 (85.4)	904 (90.5)
BMI (kg/m^2) mean (SD)	23.8 (3.4)	24.4 (3.4)	23.4 (3.6)	23.9 (3.5)
Diseases
AMI (%)	35 (5.5)	16 (8.2)	20 (12.2)	71 (7.1)
CHF (%)	147 (22.9)	72 (37.1)	87 (53.0)	306 (30.6)
HTN (%)	489 (76.3)	165 (85.1)	141 (86.0)	795 (79.6)
DM (%)	242 (37.8)	81 (41.8)	73 (44.5)	396 (39.6)
AF (%)	125 (19.5)	54 (27.8)	34 (20.7)	213 (21.3)
Anemia (%)	203 (31.7)	87 (44.8)	115 (70.1)	405 (40.5)
Hypoalbuminemia (%)	23 (3.6)	3 (1.5)	19 (11.6)	45 (4.5)
Hyperuricemia (%)	100 (15.6)	76 (39.2)	91 (55.5)	267 (26.7)
Clinical presentation
MSBP (mmHg) mean (SD)	132.6 (13.5)	133.7 (12.8)	134.9 (13.6)	132.3 (123.6–142.0)
HR (bpm) median (75% range)	72 (64–80)	70 (64–80)	74 (65–83)	72 (64–80)
Investigative variables
EF < 40% (%)	14 (2.2)	9 (4.6)	13 (7.9)	36 (3.6)
Laboratory results
NT-proBNP (pg/mL) median (75% range)	298.6 (129.1–950.2)	526.3 (174.9–1915.4)	2390.8 (749.2–7397.8)	409.8 (158.4–1783.8)
eGFR (mL/minute/1.73 m^2) median (75% range)	78.7 (70.0–89.2)	53.9 (50.8–57.2)	33.9 (19.8–39.7)	68.7 (53.1–82.3)
Na^+ (mmol/L) median (75% range)	139 (136–142)	139 (136–142)	139 (135–142)	139 (136–142)
Ka^+ (mmol/L) median (75% range)	3.9 (3.7–4.2)	4.0 (3.8–4.3)	4.2 (3.9–4.6)	4.0 (3.7–4.3)
Ca^2+ (mmol/L) median (75% range)	2.2 (2.1–2.3)	2.2 (2.1–2.3)	2.3 (2.1–2.4)	2.2 (2.1–2.3)
Drug
Diuretic use (%)	529 (82.5)	194 (100.0)	164 (100.0)	887 (88.8)

Abbreviations: AF, atrial fibrillation; AMI, acute myocardial infarction; BMI, body mass index; CHF, chronic heart failure; CKD, chronic kidney disease; DM, diabetes mellitus; EF, ejection fraction; eGFR, estimated glomerular filtration rate; HR, heart rate; HTN, hypertension; MSBP, mean systolic blood pressure; NT-proBNP, N-terminal pro-brain natriuretic peptide; SD, standard deviation.

Figure 1 (A) Non-CKD patients (n = 641): ROC curve analysis for NT-proBNP identifying CHF. (B) CKD patients (n = 358): ROC curve analysis for NT-proBNP identifying CHF. (C) non-CKD patients (n = 641): ROC curve analysis for NT-proBNP predicting death. (D) CKD patients (n = 358): ROC curve analysis for NT-proBNP predicting death. (E) CKD patients (n = 358): comparison of ROC curve predicting death between NT-proBNP and the three-variable model. (F) CKD patients (n = 358): comparison of ROC curve predicting death between NT-proBNP and the six-variable model.

Abbreviations: CHF, chronic heart failure; CKD, chronic kidney disease; DM, diabetes mellitus; eGFR, estimated glomerular filtration rate; HTN, hypertension; NT-proBNP, N-terminal pro-brain natriuretic peptide; ROC, receiver-operating characteristic.

Table 2 Hazard ratios of NT-proBNP in elderly Chinese coronary artery disease patients with and without CKD

Alla	Crude HR (95% CI)	P-value	Multiple adjusted HR (95% CI)b	P-value
No CKD	1.691 (1.504–1.901)	<0.001	1.384 (1.190–1.609)	<0.001
CKDc	1.766 (1.574–1.983)	<0.001	1.542 (1.324–1.795)	<0.001
eGFR > 45 mL/minute/1.73 m^2	2.051 (1.609–2.615)	<0.001	2.075 (1.462–2.945)	<0.001
eGFR 30–45 mL/minute/1.73 m^2	1.716 (1.340–2.198)	<0.001	1.922 (1.288–2.870)	0.001
eGFR < 30 mL/minute/1.73 m^2	1.574 (1.253–1.978)	<0.001	1.729 (1.189–2.515)	0.004

Notes:

a Cox regression all-cause mortality analyses;

b adjusted for age, gender, body mass index, acute myocardial infarction, chronic heart failure, hypertension, diabetes mellitus, atrial fibrillation, anemia, hypoalbuminemia, hyperuricemia, mean systolic blood pressure, heart rate, ejection fraction < 40%, Na⁺, Ka⁺, and Ca²⁺ levels, and diuretic use;

c separate analyses for patients with CKD and different stages of CKD.

Abbreviations: CKD, chronic kidney disease; CI, confidence interval; eGFR, estimated glomerular filtration rate; HR, hazard ratio; NT-proBNP, N-terminal pro-brain natriuretic peptide.

Figure 2 (A) Non-CKD patients (n = 641): Kaplan–Meier estimate of survival according to the cutoff point of NT-proBNP (369.5 pg/mL). (B) CKD patients (n = 358): Kaplan–Meier estimate of survival according to the cutoff point of NT-proBNP (2584.1 pg/mL).

Abbreviations: CKD, chronic kidney disease; NT-proBNP, N-terminal pro-brain natriuretic peptide.

Table 3 Prognostic value of NT-proBNP and other models in elderly Chinese patients with both coronary artery disease and chronic kidney disease

	C statistic (95% CI)	Z value	P-value
NT-proBNP	0.818 (0.774–0.857)
Age, gender, and eGFR	0.694 (0.644–0.741)	3.483	<0.001a
Age, gender, and eGFR plus NT-proBNP	0.836 (0.793–0.873)	4.735	<0.001b
Age, gender, eGFR, DM, HTN, and anemia	0.744 (0.696–0.788)	2.112	0.035a
Age, gender, eGFR, DM, HTN, and anemia plus NT-proBNP	0.853 (0.811–0.888)	4.162	<0.001b

Notes:

a P-value was drawn from comparisons between other models and NT-proBNP;

b P-value was drawn from comparisons between other models with the addition of NT-proBNP and other models.

Abbreviations: CI, confidence interval; DM, diabetes mellitus; eGFR, estimated glomerular filtration rate; HTN, hypertension; NT-proBNP, N-terminal-pro-brain natriuretic peptide.