Association of NTproBNP and cTnI with outpatient sudden cardiac death in hemodialysis patients: the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study

Table 2 Association of NTproBNP and cTnI with Sudden Cardiac Death among 503 Hemodialysis Patients of the CHOICE Study

				Model 1		Model 2		Model 3		Model 4
	Range	N (events)	Crude IR	HR (95 % CI)	p	HR (95 % CI)	p	HR (95 % CI)	p	HR (95 % CI)	p
NTproBNP, pg/mL
Continuous ^a		503 (75)		1.33 (1.21–1.46)	<0.001	1.29 (1.17–1.42)	<0.001	1.28 (1.14–1.44)	<0.001	1.27 (1.13–1.43)	<0.001
Categorical ^{b, d}
Low Category	59–1710	168 (13)	19.0	Reference		Reference		Reference		Reference
Mid Category	1728–7269	168 (22)	35.3	1.99 (1.25–3.14)	0.003	1.99 (1.16–3.41)	0.012	1.67 (1.01–2.77)	0.045	1.39 (0.79–2.44)	0.252
High Category	7350–273502	167 (40)	78.9	4.49 (2.61–7.71)	<0.001	3.90 (2.07–7.34)	<0.001	3.32 (1.67–6.59)	0.001	3.03 (1.56–5.89)	0.001
p-trend				<0.001		<0.001		0.001		0.001
Troponin I, ng/mL
Continuous ^a		503 (75)		1.19 (1.06–1.32)	0.002	1.22 (1.07–1.38)	0.002	1.18 (1.02–1.36)	0.027	1.17 (0.98–1.40)	0.084
Categorical ^{b, c}
Low Category	<0.015	336 (41)	32.8	Reference		Reference		Reference		Reference
Mid Category	0.015–0.039	85 (18)	57.5	1.82 (1.06–3.10)	0.029	1.83 (1.04–3.20)	0.036	1.56 (0.88–2.80)	0.128	1.62 (0.89–2.95)	0.11
High Category	0.040–3.09	82 (16)	64.0	2.14 (1.46–3.13)	<0.001	2.48 (1.51–4.06)	<0.001	1.98 (1.15–3.39)	0.013	1.91 (0.98–3.72)	0.058
p-trend				<0.001		<0.001		0.011		0.048

Abbreviations: Troponin I, cTnI; Hazard Ratio, HR; N-terminal pro-brain natriuretic peptide, NTproBNP. Incidence rate per 1000 person-years
^a Hazard ratio per doubling of the marker; modeled as ln(marker)/ln(2). Modeled using Cox proportional hazards regression
^b Hazard ratio with the low category as the reference group. Modeled using Cox proportional hazards regression
^c For cTnI, low category refers those patients with TNI below the limit of detection (<0.015 ng/mL; n = 336). Remaining patients are divided into two groups at the median. Mid category refers to the group below median cTnI for those with detectable values (<0.040 ng/mL; n = 85) and high category refers to those with values at or above median (≥0.040 ng/mL; n = 82)
^d For NTproBNP, low, mid and high category refers to the lowest, middle and highest tertiles of NTproBNP
Model 1: Unadjusted
Model 2: Adjusted for demographics including age, sex and race
Model 3: Adjusted for variables in model 2 + clinical factors including smoking status (ever versus never), Index of Coexistent Disease (ICED) score, diabetes, cardiovascular disease, congestive heart failure, body mass index and systolic blood pressure
Model 4: Adjusted for variables in model 3 + left ventricular hypertrophy, β-blocker use and laboratory tests including hemoglobin, serum albumin, serum potassium, serum bicarbonate, serum corrected calcium and serum phosphate

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