Download Prolonged QT interval is linked to all‐cause and cardiac mortality in

Prolonged QT interval is linked to all-cause and cardiac mortality in
chronic peritoneal dialysis patients
Huey-Liang Kuo1,2,3, Yao-Lung Liu2,3, Chih-Chia Liang2, Chiz-Tzung Chang2,3, Su-Ming
Wang2,3, Jiung-Hsiun Liu2,3, Hsin-Hung Lin2,3, I-Kuan Wang2,3, Ya-Fei Yang2,3, Che-Yi Chou2,3,
Chiu-Ching Huang2,3
1
Graduate Institute of Clinical Medical Science, College of Medicine, China Medical
University, Taichung 40402, Taiwan
2
Kidney Institute and Division of Nephrology, Department of Internal Medicine, China
Medical University Hospital, Taichung 40447, Taiwan
3
College of Medicine, China Medical University, Taichung 40402, Taiwan
Correspondence: Che-Yi Chou MD, PhD
Address of corresponding author
Kidney Institute and Division of Nephrology, Department of Internal Medicine, China Medical
University Hospital, No.2, Yu-der Road, North District, Taichung 40447, Taiwan
Tel: +886-4-22052121-3483, Fax: +886-4-22058883
E-mail: [email protected]
Running title: QT interval and mortality in PD patients
This article has been accepted for publication and undergone full peer review but has not been
through the copyediting, typesetting, pagination and proofreading process which may lead to
differences between this version and the Version of Record. Please cite this article as doi:
10.1111/nep.12808
This article is protected by copyright. All rights reserved.
Abstract
Prolonged QT interval is related to changes of electrolytes in hemodialysis (HD) and is
associated with all-cause mortality in HD patients. It is unknown if prolonged QT interval is
associated with all-cause mortality in peritoneal dialysis (PD) patients as the electrolytes were
relatively stable in PD. We therefore investigated the association of prolonged QT interval
and all-cause mortality in chronic PD patients.
Methods
The QT intervals were measured in 2003 and all patients were followed to Dec 2012. A
prolonged QT interval was defined as a QT interval > 450 ms. The association of prolonged
QT interval with all-cause and cardiac-specific mortality was analyzed using Cox regression
and Kaplan-Meier analysis.
Results
Of 306 patients, 196 (64%) patients had prolonged QT interval. The incidence density rate
was 9.7 per 100 persons-years for all-cause mortality and 5.6 for cardiac specific mortality in
patients with prolonged QT interval. Prolonged QT interval was associated with all-cause
mortality with a hazard ratio (HR) of 1.59 [95% confidence interval (CI): 1.06-2.39, p = 0.03]
and cardiac mortality (HR: 1.66, 95% CI: 1.00-2.78, p = 0.05) with adjustments for age,
gender, diabetes, and vintage of dialysis. Longer QT interval (> 500 ms, 450-500 ms, and <
450 ms) was significantly associated with a worse overall survival (p = 0.03, log-rank test)
This article is protected by copyright. All rights reserved.
and cardiac mortality free survival (p = 0.05, log-rank test).
Conclusions
Prolonged QT interval was associated with all-cause and cardiac mortality in patients on
peritoneal dialysis. The association is independent of patient’s age and diabetes.
Keywords: peritoneal dialysis, QT interval, mortality, cardiac mortality
This article is protected by copyright. All rights reserved.
Introduction
Prolonged QT interval is associated with all-cause and cardiac mortality in patients on
hemodialysis (HD) as well as general population
1, 2
. The QT interval measured using
electrocardiogram (ECG) in patients receiving HD may be inaccurate 3 because of changes of
electrolyte (potassium, calcium, and magnesium) during HD treatment
4-8
. QT dispersion is
the difference between the longest and the shortest QT interval. The QT dispersion was
associated with all-cause mortality and cardiovascular mortality in HD patients and peritoneal
dialysis (PD) patients 9. The QT dispersion is generally considered as a better predictor of
cardiac mortality in HD patients because the QT dispersion was not affected by HD treatment
5
. It is unknown if prolonged QT interval is associated all-cause mortality and cardiac
mortality in peritoneal dialysis (PD) patients. We hypothesize that the QT interval may be
associated with mortality in PD patients because serum potassium and calcium were not
rapidly changed in PD patients as that did in HD patients. The aim of the study was to
investigate the association of prolong QT interval and all-cause mortality as well as cardiac
mortality in PD patients. Medications that may be related to prolonged QT interval were
recorded and were taken into consideration in this study.
This article is protected by copyright. All rights reserved.
Methods
This study was proved by the internal review board of China Medical University Hospital
(IRB104-REC2-045) and a written informed consent was obtained for all participants. All
chronic PD patients in China Medical University Hospital in 2003 were enrolled. None of the
patients had HD before PD. All patients were prospectively followed to the date of changing
of dialysis mode (HD or kidney transplant), loss of follow-up, death, or Dec 2012. 12 (3.9%)
patients were transferred to other hospital and the last known status of these patients was
recorded. 72 (23.5%) patients were transferred to HD and 6 (2%) patients underwent kidney
transplant. These patients were followed to the date of HD or kidney transplant. Cardiac
mortality was defined as death from myocardial infarction, cardiac perforation or pericardial
tamponade, arrhythmia or conduction abnormality, stroke, procedural complications, or any
death in which a cardiac cause could not be excluded
10
. The QT interval was calculated as
the mean QT interval from 12 leads ECG using Bazett’s formula
11
and rate corrected. The
ECG were obtained in regular out-patient visits and at least two ECGs measurements were
recorded for each patient. The average QT interval was used in the analysis. Prolonged QT
interval was defined as a QT interval > 450ms.
The body mass index (BMI), white blood cell counts (WBC), hemoglobin, platelet, blood
urea nitrogen (BUN), creatinine, serum calcium, phosphorus, albumin, cholesterol,
This article is protected by copyright. All rights reserved.
triglyceride, fasting blood glucose (FBG), ferritin, intact parathyroid hormone (iPTH),
24-hour urine creatinine clearance, and Kt/V were measured with the measurements of ECGs.
The average values were used if more than two values are available. Medications that may be
related to QT interval including alfa-blockers, beta-blockers, cisapride, amiodarone, tricyclic
antidepressants (TCA) for more than 3 months in 2003 were recorded. The ratio of creatinine
concentration in dialysate to plasma at the completion of the 4 h dwell period (D/Pcre) was
evaluated to estimate low-molecular-weight solute transport. All the patients were classified
into peritoneal equilibration test (PET) categories by the value of D/Pcre. Then they were
divided into four groups: low (L) transporters (D/Pcre <0.55), low-average (LA) transporters
(D/Pcre: 0.55-0.64), high-average (HA) transporters (D/Pcre 0.65-0.80), and high (H)
transporters (D/Pcre > 0.80) 12.
Coronary artery disease (CAD) was defined as a positive exercise test, angiography showing
at least one stenosis of more than 50%, or positive scintigraphy
13
. Diabetes mellitus (DM)
was defined as use of insulin or a hypoglycemic agent, a fasting plasma glucose level of 126
mg/dL or more 14. Underling disease of CKD including chronic glomerular nephritis (CGN),
diabetes mellitus (DM), and hypertension (HTN) was diagnosed by the physician in primary
care who enrolled the patient. A study nurse performed all reviewing of medical records and
the study nurse consulted one physician if any uncertain condition exists in the reviewing.
This article is protected by copyright. All rights reserved.
The study nurse and physician were blind to the aim of the study and the analysis was
performed by another physician. Hypocalcemia was defined as a serum calcium less than 8.0
mg/dl and hypokalemia was defined as a serum potassium less than 3.5 meq/L.
Statistical analysis
Data are reported as mean ± standard deviation, median (interquartile range) or frequency
(percentage). All continuous variables were tested using for Skewness and kurtosis test for
their normality. Testing for statistical significance was conducted using Student’s t test for
parametric variables, Kolmogorov-Smirnov test for non-parametric variables, and chi-square
test for categorical variables. Factors that may be associated with prolonged QT interval were
analyzed using logistic regression. The factors with a p < 0.05 were considered as
confounders. The confounders and well-known prognostic factors in the literature were
further analyzed using multivariable Cox regression. A hazard ratio (HR) and 95%
confidence interval (CI) was calculated. Patient’s survival according the QT interval was
analyzed using Kaplan-Meier analysis with adjustments for confounders. All analysis was
performed using Stata version 12 SE (StataCorp, TX, USA).
Results
Three hundred and six chronic PD patients including 114 male and 192 female with mean age
of 59.7 ± 14.6 years old were enrolled (Table 1). The incidence of overall mortality was 7.4
This article is protected by copyright. All rights reserved.
per 100 patients/year and the incidence of cardiac mortality was 4.4 per 100 patients/year.
The median of QT interval was 449 ms (interquartile range: 426-474). Of 306 patients, 112
(36.6%) patients had a high-average transport status and 137 (44.8%) patients had a
low-average transport status. CGN was the underlying kidney disease in 171 (55.9%) patients
and DM was the underlying kidney disease in 78 (25.5%) patients. Thirty-two (10.5%)
patients had comorbid CAD, 105 (34.3%) patients had comorbid DM, and 91 (29.7%)
patients had comorbid HTN. There were 63 (20.6%) patients on alfa-blocker, 98 (32%)
patients on beta-blocker, 32 (10.5%) patients on cisapride, 3 (1.0%) patients on amiodarone
and 4 (1.3%) patients on TCA respectively. The average Kt/V was 2.1 ± 0.5 in the study
population.
There were 196 (64%) patients had a QT interval > 450 ms (Table 1). The incidence of
overall mortality was 9.7 per 100 patient/year in patients with prolonged QT interval and 4.3
in patients without. The incidence of cardiac mortality was 5.6 per 100 patient/year in
patients with prolonged QT interval and 2.7 in patients without. Patients with prolonged QT
interval were older and were predominately female. The follow-up was shorter and the
percentage of DM was higher in patients with prolonged QT interval. The serum creatinine
and serum albumin was lower in patients with prolonged QT interval. The FBG was higher in
patients with prolonged QT interval than those without. The association of medications and
prolonged QT interval was analyzed using univariate logistic regression. None of the
This article is protected by copyright. All rights reserved.
medications (alfa blockers, beta-blockers, cisapride, amiodarone, and TCA) was associated
with a higher risk of prolonged QT interval.
Factors associated with prolonged QT interval were analyzed using logistic regression (Table
2). Patients’ age (p < 0.01), vintage of dialysis (p < 0.02), male gender (p<0.01), PET (p =
0.03), DM (p = 0.02), creatinine (p < 0.01), and serum albumin (p = 0.01) were associated
with prolonged QT interval. As age, vintage of dialysis, gender, DM were well-known
confounders, the association of prolonged QT interval and all-cause mortality/cardiac
mortality was analyzed using multivariable Cox regression with adjustments for age, vintage
of dialysis, gender, and diabetes (Table 3). Prolonged QT interval was associated with
all-cause mortality (HR: 1.59, 95% CI: 1.06-2.39, p = 0.03) and cardiac mortality (HR: 1.66,
95% CI: 1.00-2.78, p = 0.05). The serum albumin was associated with cardiac mortality (HR:
0.45, 95% CI: 0.29-0.70, p < 0.01) but was not associated with all-cause mortality (p = 0.50).
PET, CAD, creatinine were not significantly associated with all-cause mortality and cardiac
mortality in the multivariable analysis. The survival curve according to QT interval (< 450 ms,
450-500 ms, and > 500 ms) for all-cause mortality with adjustments for age, sex, diabetes,
and vintage of dialysis is shown in Figure 1A. The patients with QT interval > 500 ms had the
lowest survival, followed by the patients with QT interval 450-500 ms, and the patients with
QT interval < 450 ms had the best survival (p = 0.03, log-rank test). The survival curve for
cardiac mortality with adjustments for age, diabetes, and albumin is shown in Figure 1B. The
This article is protected by copyright. All rights reserved.
survival curve of patients with QT interval < 450 was better than that of patients with QT
interval 450-500 ms and that of patients with QT > 500 ms (p = 0.05).
Discussions
In this cohort of PD patients that 64% of patients had prolonged QT interval, it was clearly
showed that prolonged QT interval was associated with all-cause mortality and cardiac
mortality. The high prevalence of patients with prolonged QT interval was also noted in other
studies 15-17. We further demonstrated that patients with QT interval > 500 ms were associated
with a worse survival than those with QT interval between 450 to 500 ms. Among
confounders, patients age, sex, vintage of dialysis, and diabetes were associated with both
all-cause mortality and cardiac mortality. The multivariable Cox regression with adjustments
for age, sex, vintage of dialysis, and diabetes were used in this study. PET, creatinine, serum
albumin, CAD, and Kt/V were associated with all-cause mortality in univariable analysis but
were not significantly associated with all-cause mortality in multivariable analysis. This may
be explained by a collinearity of PET, albumin, and Kt/V.
In the medications, we found that cisapride was neither associated with prolonged QT
interval nor associated with all-cause mortality. This was observed in previous studies in HD
patients as well
18, 19
. A lower serum creatinine may indicate lower physical activity or
malnutrition. The lower physical activity and malnutrition may be responsible for the
This article is protected by copyright. All rights reserved.
increased overall and cardiac mortality. The category of peritoneal equilibration test is not
associated with the QT prolongation. Other confounders identified include patient’s age and
DM, age and DM were well-known confounding factors in patients receiving PD. In addition,
patients’ albumin was associated with cardiac mortality but not overall mortality.
There were some limitations of this observational study. Patients who switched from PD to
HD or kidney transplant were followed to the date of changes of modality. The true incidence
density rate of overall mortality and cardiac mortality may be higher than that reported in this
study. The QT intervals were obtained using two ECGs with adjustments for heart rate in
2003 and the QT intervals may be different through out of the follow-up period. We reviewed
the medications including alfa-blocker, beta-blocker, cisapride, amiodarone, and TCA for 3
months at the enrollment. The medications prescribed before the date of patients’ death were
not recorded in this study.
In conclusion, prolonged QT interval is associated with higher overall mortality and cardiac
mortality in patients receiving peritoneal dialysis. This association is independent of patient’s
age and comorbid diabetes.
This article is protected by copyright. All rights reserved.
Conflict of interest statement
The results presented in this paper have not been published previously in whole or part. The
authors have no conflicts of interest regarding this study. There is no financial support for this
study.
References
1
Genovesi S, Rossi E, Nava M, Riva H, De Franceschi S, Fabbrini P, et al. A case series of
chronic haemodialysis patients: mortality, sudden death, and QT interval. Europace. 2013; 15:
1025-33.
2
de Bruyne MC, Hoes AW, Kors JA, Hofman A, van Bemmel JH, Grobbee DE. Prolonged
QT interval predicts cardiac and all-cause mortality in the elderly. The Rotterdam Study. Eur
Heart J. 1999; 20: 278-84.
3
Thomson BK, Momciu B, Huang SH, Chan CT, Urquhart B, Skanes A, et al. ECG
machine QTc intervals are inaccurate in hemodialysis patients. Nephron Clin Pract. 2013; 124:
113-8.
4
Cupisti A, Galetta F, Morelli E, Tintori G, Sibilia G, Meola M, et al. Effect of hemodialysis
on the dispersion of the QTc interval. Nephron. 1998; 78: 429-32.
5
Ljutic D. Haemodialysis increases QTc interval but not QTc dispersion in ESRD patients
without manifest cardiac disease. Nephrol Dial Transplant. 2003; 18: 1414; author reply 14.
6
Afshinnia F, Doshi H, Rao PS. The effect of different dialysate magnesium concentrations
on QTc dispersion in hemodialysis patients. Ren Fail. 2012; 34: 408-12.
7
Di Iorio B, Torraca S, Piscopo C, Sirico ML, Di Micco L, Pota A, et al. Dialysate bath and
QTc interval in patients on chronic maintenance hemodialysis: pilot study of single dialysis
effects. J Nephrol. 2012; 25: 653-60.
8
Nappi SE, Virtanen VK, Saha HH, Mustonen JT, Pasternack AI. QTc dispersion increases
during hemodialysis with low-calcium dialysate. Kidney Int. 2000; 57: 2117-22.
9
Beaubien ER, Pylypchuk GB, Akhtar J, Biem HJ. Value of corrected QT interval
dispersion in identifying patients initiating dialysis at increased risk of total and cardiovascular
mortality. Am J Kidney Dis. 2002; 39: 834-42.
10 Mehran R, Lansky AJ, Witzenbichler B, Guagliumi G, Peruga JZ, Brodie BR, et al.
Bivalirudin in patients undergoing primary angioplasty for acute myocardial infarction
(HORIZONS-AMI): 1-year results of a randomised controlled trial. Lancet. 2009; 374:
This article is protected by copyright. All rights reserved.
1149-59.
11 Ahnve S. Correction of the QT interval for heart rate: review of different formulas and the
use of Bazett's formula in myocardial infarction. Am Heart J. 1985; 109: 568-74.
12 Twardowski ZJ. PET--a simpler approach for determining prescriptions for adequate
dialysis therapy. Adv Perit Dial. 1990; 6: 186-91.
13 Dormandy JA, Charbonnel B, Eckland DJ, Erdmann E, Massi-Benedetti M, Moules IK, et
al. Secondary prevention of macrovascular events in patients with type 2 diabetes in the
PROactive Study (PROspective pioglitAzone Clinical Trial In macroVascular Events): a
randomised controlled trial. Lancet. 2005; 366: 1279-89.
14 Gottlieb DJ, Punjabi NM, Newman AB, Resnick HE, Redline S, Baldwin CM, et al.
Association of sleep time with diabetes mellitus and impaired glucose tolerance. Arch Intern
Med. 2005; 165: 863-7.
15 Di Loreto P, Ronco C, Vescovo G. Long QT, alteration of calcium-phosphate product,
prevalence of ventricular arrhythmias and sudden death in peritoneal dialysis patients: a Holter
study. Italian Journal of Medicine. 2012; 6: 99-104.
16 Kantarci G, Ozener C, Tokay S, Bihorac A, Akoglu E. QT dispersion in hemodialysis and
CAPD patients. Nephron. 2002; 91: 739-41.
17 Yildiz A, Akkaya V, Sahin S, Tukek T, Besler M, Bozfakioglu S, et al. QT dispersion and
signal-averaged electrocardiogram in hemodialysis and CAPD patients. Perit Dial Int. 2001;
21: 186-92.
18 Mathis AS, Costeas C, Barone JA. Retrospective analysis of the effects of cisapride on the
QT interval and QT dispersion in chronic hemodialysis patients. Am J Kidney Dis. 2001; 38:
1284-91.
19 Hentges MJ, Gunderson BW, Lewis MJ. Retrospective analysis of cisapride-induced QT
changes in end-stage renal disease patients. Nephrol Dial Transplant. 2000; 15: 1814-8.
This article is protected by copyright. All rights reserved.
Table 1. Clinical characteristics of patients with and without prolonged QT interval
All
n=306
Characteristics
±14.6
37.3
±2.6
Prolong QT(-)
n=110
Age (year)
Male gender n (%)
Vintage of dialysis (year)
Mortality (per 100 pts/year)
Cardiac (per 100 pts/year)
59.7
114
3.2
56.4
52
3.3
BMI (kg/m2)
Follow-up (year)
PET
H
HA
LA
23.3
3.2
±3.3
1.3-10
23.0
4.2
±3.2
1.6-10.9
30
112
137
9.8
36.6
44.8
10
37
55
L
Underlying disease
DM
27
8.8
78
CGN
HTN
Comorbidity
CAD
DM
HTN
Medication
Alfa blockers
Beta blockers
61.5
62
3.2
p
±15.2
31.6
±2.4
<0.01
<0.01
0.74
-
23.4
3.8
±3.3
1.4-9.9
0.36
0.01
9.1
33.6
50
20
75
82
10.2
38.3
41.8
8
7.3
19
9.7
25.5
19
17.3
59
30.1
0.01
171
25
55.9
8.2
65
11
59.1
10
106
14
54.1
7.1
0.40
0.38
32
105
91
10.5
34.3
29.7
9
28
33
8.2
25.5
30
23
77
58
11.7
39.3
29.6
0.33
0.01
0.94
63
98
20.6
32.0
21
38
19.1
34.6
42
60
21.4
30.6
0.24
0.50
Cisapride
Amiodarone
TCA
Hemoglobin (g/dl)
BUN (mg/dl)
Creatinine (mg/dl)
Potassium (meq/l)
Hypokalemia n(%)
32
3
4
9.6
51
10.9
4.1
68
10.5
1.0
1.3
±1.0
±17
±3.4
±0.8
22.2
9
0
1
9.8
51.2
11.5
4.0
23
8.2
0
0.9
±1.2
±16.5
±4.0
±0.7
20.9
23
3
3
9.6
51.5
10.5
4.1
45
11.7
1.5
1.5
±0.9
±16.6
±2.9
±0.8
23.0
0.33
0.19
0.65
0.12
0.93
<0.01
0.63
0.68
Calcium (mg/dl)
Hypocalcemia n(%)
Phosphorus (mg/dl)
Albumin (g/dl)
9.8
51
5.2
3.3
±0.9
16.7
±1.6
±0.5
9.8
15
5.1
3.4
±0.8
13.6
±1.5
±0.5
9.8
36
5.3
3.3
±1.0
18.4
±1.6
±0.5
0.82
0.29
0.31
0.01
7.4
4.4
±12.9
47.3
±2.8
4.3
2.7
Prolong QT(+)
n=196
9.7
5.6
This article is protected by copyright. All rights reserved.
0.57
Cholesterol (mg/dl)
Triglyceride (mg/dl)
FBG (mg/dl)
iPTH (pg/ml)
Ferritin (ng/ml)
CCr (ml/min)
Kt/V
108
183
143
200.7
348.8
54.8
2.1
±79
±134
±64
75.5-437.9
153.6-634.9
±15
0.5
101.9
±81.2
161.9
±83.7
136
±65
244.1 95.6-494.1
334.4 163-653
57
±17
2.2
±0.5
115.7
206.4
160
178.3
374.9
53
2.1
±82.8
±171.8
±82
62.7-412.4
153.6-634.9
±13
±0.4
BMI: body mass index, PET: peritoneal equilibration test, H: high transporters, HA;
high-average transporters, LA: low-average transporters, L: low transporters, DM: diabetes
mellitus, CGN: chronic glomerulonephritis, HTN: hypertension, CAD: coronary artery
disease, TCA: tricyclic antidepressants, BUN: blood urea nitrogen, Hypocalcemia: serum
calcium less than 8.0 mg/dl, Hypokalemia: serum potassium less than 3.5 meq/L, FBG:
fasting blood glucose, iPTH: intact parathyroid hormone, CCr: 24 hour urine creatinine
clearance. Kt/V is a number used to quantify hemodialysis and peritoneal dialysis treatment
adequacy. K - dialyzer clearance of urea; t - dialysis time; V - volume of distribution of urea,
approximately equal to patient's total body water. Hypokalemia (<3.5meq/l). Hypocalcemia
(<8.5mg/dl)
This article is protected by copyright. All rights reserved.
0.74
0.11
0.02
0.15
0.92
0.02
0.53
Table 2. Factors associated with prolonged QT interval
Factors
OR
95 % CI
P
Age (per year)
Vintage of dialysis (per year)
Male gender
PET (per category)
DM
HTN
1.02
0.89
0.52
0.74
1.89
0.98
1.01
0.80
0.32
0.57
1.13
0.59
1.04
0.98
0.83
0.96
3.17
1.63
<0.01
0.02
<0.01
0.03
0.02
0.94
CAD
Medication
Alfa blockers
Beta blockers
Cisapride
Hemoglobin (per g/dl)
1.49
0.66
3.35
0.33
1.16
0.84
1.49
0.84
0.64
0.51
0.66
0.66
2.08
1.37
3.35
1.05
0.63
0.48
0.33
0.12
Creatinine (per mg/dl)
Albumin (per g/dl)
Hypokalemia (<3.5meq/l)
0.91
0.51
1.13
0.85
0.30
0.64
0.98
0.86
1.99
<0.01
0.01
0.68
Hypocalcemia(<8.5mg/dl)
FBG (per 10 mg/dl)
CCr (per ml/min)
Kt/V
1.43
1.04
0.95
0.78
0.74
0.99
0.84
0.46
2.74
1.08
1.07
1.33
0.29
0.10
0.42
0.07
PET: peritoneal equilibration test, DM: diabetes mellitus, HTN: hypertension, CAD: coronary
artery disease, Hypocalcemia: serum calcium less than 8.0 mg/dl, Hypokalemia: serum
potassium less than 3.5 meq/L, FBG: fasting blood glucose, CCr: 24 hour urine creatinine
clearance. OR: odds ratio. CI: confidence interval. CCr: 24 hour urine creatinine clearance.
Kt/V is a number used to quantify hemodialysis and peritoneal dialysis treatment adequacy. K
- dialyzer clearance of urea; t - dialysis time; V - volume of distribution of urea,
approximately equal to patient's total body water.
This article is protected by copyright. All rights reserved.
Table 3. Hazard ratio (HR) of prolonged QT interval and confounders for all-cause mortality
and cardiac mortality in multivariable Cox regression with adjustments for age, gender,
diabetes, and vintage of dialysis
Confounders
All-cause mortality
HR
95 % CI
Cardiac mortality
p
HR
95 % CI
p
Prolonged QT interval
PET (per category)
CAD
Creatinine (per mg/dl)
1.59
0.84
1.39
0.97
1.06
0.69
0.83
0.90
2.39
1.02
2.34
1.05
0.03
0.07
0.22
0.44
1.66
0.85
1.74
1.02
1.00
0.66
0.90
0.92
2.78
1.09
3.37
1.12
0.05
0.21
0.10
0.72
Albumin (per g/dl)
Kt/V
0.88
0.73
0.60
0.48
1.28
1.10
0.50
0.14
0.45
0.68
0.29
0.39
0.70
1.19
<0.01
0.18
HR: hazard ratio, CI: confidence interval, PET: peritoneal equilibration test, CAD: coronary
artery disease. Kt/V is a number used to quantify hemodialysis and peritoneal dialysis
treatment adequacy. K - dialyzer clearance of urea; t - dialysis time; V - volume of
distribution of urea, approximately equal to patient's total body water.
This article is protected by copyright. All rights reserved.
Figure 1. Survival curve of patients according to QT interval (< 450 ms, 450-500 ms, and >
500ms) for all-cause mortality with adjustments for age, gender, diabetes, and vintage of
dialysis (A) and for cardiac mortality with adjustments for age, gender, diabetes, vintage of
dialysis, and serum albumin (B)
This article is protected by copyright. All rights reserved.