TABLE 1. Baseline demographics, biochemical data and dialysis characteristics in patients with no fluid overload (OH/ECW ≤ 7%), mild fluid overload (OH/ECW >7.0 to 15%), and moderate to severe fluid overload (OH/ECW>15.0%).
|
|
fluid overload
|
|
|
all cases
|
no
|
mild
|
moderate to severe
|
P-value
|
No. of patients
|
269
|
47
|
58
|
164
|
-
|
Incident: prevalent
|
51:218
|
4:43
|
9:49
|
38:126
|
0.058 1
|
Duration of PD (months)
|
1.9 (1.4 to 3.6)
|
3.7 (1.7 to 25.3)
|
2.6 (1.6 to 4.4)
|
1.8 (1.1 to 2.7) a,b
|
<0.0001 2
|
Male (%)
|
58.7%
|
51.1%
|
58.6%
|
61.0%
|
0.48 1
|
Age (year)
|
59.7 ± 11.5
|
55.9 ± 9.1
|
60.4 ± 11.5
|
60.5 ± 12.0 c
|
0.04 3
|
Blood pressure (mmHg)
|
|
|
|
|
|
Systolic
|
135.3 ± 21.0
|
125.6 ± 19.6
|
133.8 ± 19.2
|
138.7 ± 21.2 b
|
0.001 3
|
Diastolic
|
73.5 ± 14.0
|
75.2 ± 12.8
|
71.3 ± 10.6
|
73.8 ± 15.3
|
0.34 3
|
Causes of renal failure, no. of cases (%)
|
|
|
|
|
<0.0001 1
|
Diabetic nephropathy
|
123 (45.7%)
|
4 (8.5%)
|
22 (37.9%)
|
97 (59.1%)
|
|
Glomerulonephritis
|
65 (24.2%)
|
23 (48.9%)
|
16 (27.6%)
|
26 (15.9%)
|
|
Hypertensive nephrosclerosis
|
27 (10.0%)
|
4 (8.5%)
|
10 (17.2%)
|
13 (7.9%)
|
|
Polycystic kidney
|
14 (5.2%)
|
4 (8.5%)
|
4 (6.9%)
|
6 (3.7%)
|
|
Obstructive uropathy
|
14 (5.2%)
|
4 (8.5%)
|
3 (5.2%)
|
7 (4.3%)
|
|
Others / unknown
|
26 (9.6%)
|
8 (17.0%)
|
3 (5.1%)
|
15 (9.1%)
|
|
Comorbidities, no. of cases (%)
|
|
|
|
|
|
Diabetes
|
147 (54.6%)
|
9 (19.1%)
|
25 (43.1%)
|
113 (68.9%)
|
<0.0001 1
|
Ischemic heart disease
|
61 (22.7%)
|
7 (14.9%)
|
10 (17.2%)
|
44 (26.8%)
|
0.12 1
|
Cerebrovascular disease
|
60 (22.3%)
|
6 (12.8%)
|
15 (25.9%)
|
39 (23.8%)
|
0.21 1
|
Peripheral vascular disease
|
17 (6.3%)
|
0 (0%)
|
2 (3.4%)
|
15 (9.1%)
|
0.045 1
|
Charlson’s Comorbidity Index
|
5.5 ± 2.3
|
4.3 ± 1.8
|
5.4 ± 2.5 d
|
5.8 ± 2.2 b
|
<0.0001 1
|
Laboratory parameters
|
|
|
|
|
|
Hemoglobin (g/dL)
|
9.3 ± 1.4
|
9.6 ± 1.4
|
9.5 ± 1.4
|
9.1 ± 1.4
|
0.054 3
|
Albumin (g/L)
|
34.7 ± 4.5
|
37.9 ± 2.8
|
35.3 ± 4.4 e
|
33.5 ± 4.4 a,b
|
<0.0001 3
|
Peritoneal transport
|
|
|
|
|
|
D/P creatinine at 4 hour
|
0.66 ± 0.14
|
0.58 ± 0.12
|
0.68 ± 0.12 e
|
0.67 ± 0.14 b
|
<0.0001 3
|
Low transporter (<0.5)
|
33 (12.5%)
|
12 (26.1%)
|
3 (5.2%)
|
18 (11.4%)
|
0.002 1
|
Low-average transporter (0.5-0.65)
|
92 (33.8%)
|
21 (45.7%)
|
22 (37.9%)
|
47 (29.7%)
|
High-average transporter (0.66-0.81)
|
100 (36.8%)
|
12 (26.1%)
|
12 (39.7%)
|
65 (41.1%)
|
High transporter (>0.81)
|
40 (14.7%)
|
1 (2.2%)
|
10 (17.2%)
|
28 (17.7%)
|
Dialysis characteristics
|
|
|
|
|
|
Use of icodextrin at baseline, no. of cases (%)
|
19 (7.1%)
|
2 (4.3%)
|
4 (6.9%)
|
13 (7.9%)
|
0.69 3
|
APD, no. of cases (%)
|
36 (13.4%)
|
9 (19.1%)
|
8 (13.8%)
|
19 (11.6%)
|
0.40 3
|
Dialysis adequacy
|
|
|
|
|
|
Weekly total Kt/V
|
2.00 ± 0.79
|
2.24 ± 0.56
|
2.07 ± 0.84
|
1.92 ± 0.82
|
0.09 3
|
Residual GFR (ml/min/1.73m2)
|
3.53 ± 2.90
|
3.63 ± 2.75
|
3.08 ± 2.94
|
3.66 ± 2.93
|
0.52 3
|
Residual urine volume (L)
|
0.97 ± 0.79
|
0.97 ± 0.81
|
0.88 ± 0.85
|
1.0 ± 0.77
|
0.74 3
|
NPNA (g/kg/day)
|
1.07 ± 0.38
|
1.18 ± 0.28
|
1.06 ± 0.37
|
1.04 ± 0.40
|
0.18 3
|
Continuous variables were expressed as mean ± standard deviation or median (interquartile range) for normally distributed and non-normally distributed variables respectively.
Abbreviations: APD, automated peritoneal dialysis, APD; D/P, dialysate-to-plasma concentration ratio; GFR, glomerular filtration rate; NPNA, normalized protein nitrogen appearance; OH/ECW: ratio of overhydration to extracellular water; PD, peritoneal dialysis.
1 Data were compared by Chi-square test
2 Data were compared by Kruskal-Wallis test
3 Data were compared by one-way ANOVA
a Moderate to severe fluid overload vs mild fluid overload, P <0.01
b Moderate to Severe fluid overload vs. normohydration, P <0.01
c Moderate to Severe fluid overload vs. normohydration, P <0.05
d Mild fluid overload vs. normohydration, P <0.05
e Mild fluid overload vs. normohydration, P <0.01
TABLE 2. Moderators of volume status (relative hydration index) by multivariate mixed linear model
Covariates
|
Estimated changes (95% confidence interval)
|
P-value
|
Age (per 10 year)
|
-0.9% (-1.7% to -1.2%)
|
0.02
|
Male sex
|
1.8% (-0.2% to 3.9%)
|
0.08
|
Diabetes (versus no diabetes)
|
7.3% (5.5% to 9.1%)
|
<0.0001
|
Systolic blood pressure (per 10mm Hg)
|
0.8% (0.5% to 1.1%)
|
<0.0001
|
Albumin (per 10g/L)
|
-3.5% (-5.0% to -2.1%)
|
<0.0001
|
Hemoglobin (per 1g/dL)
|
-0.7% (-1.2% to -0.2%)
|
0.004
|
Weekly Kt/V (per 0.1 unit)
|
-0.2% (-0.4% to -0.1%)
|
0.006
|
Residual urine volume (per 100ml)
|
-0.05% (-0.2% to 0.1%)
|
0.45
|
D/P creatinine (at 4 hour) at baseline (per 0.1 unit)
|
0.04% (-0.6% to 0.5%)
|
0.89
|
Lean tissue index (per kg/m2)
|
-0.9% (-1.2% to -0.5%)
|
<0.0001
|
Fat tissue index (per kg/m2)
|
-0.5% (-0.8% to -0.3%)
|
<0.0001
|
Normalized protein nitrogen appearance (per g/kg/day)
|
2.1% (-1.9% to 5.9%)
|
0.31
|
TABLE 3. Change of volume status over time in different subgroups
|
Baseline RHI (%)
|
Adjusted difference in RHI between groups at Year 0
|
Adjusted difference in RHI between groups at Year 1
|
Mean annual change in RHI (% per year)
|
Adjusted mean difference in annual change in RHI between groups (% per year)
|
Baseline volume status
|
|
RHI > 7%
|
20.8 (19.5 to 22.1)
|
0 (reference)
|
0 (reference)
|
-0.6 (-1.4 to 0.3)
|
0 (reference)
|
RHI ≤ 7%
|
6.3 (3.4 to 9.2)
|
-14.5 (-17.7 to -11.3) a
|
-6.1 (-9.2 to -3.0) a
|
2.6 (1.1 to 4.2)
|
3.2 (1.5 to 4.9) a
|
Baseline residual urine output
|
|
≥ 200ml/day
|
18.8 (17.3 to 20.4)
|
0 (reference)
|
0 (reference)
|
-0.3 (-1.3 to 0.7)
|
0 (reference)
|
< 200ml/day
|
16.3 (12.7 to 19.8)
|
2.6 (-1.4 to 6.6)
|
-3.7 (-7.7 to 0.4) b
|
1.1 (-1.0 to 3.1)
|
1.4 (-0.9 to 3.7)
|
Abbreviations: RHI, relative hydration index
Data are presented as mean (95% confidence interval)
The model was adjusted for age, gender, diabetes, baseline transporter status, Kt/V, residual urine output, systolic blood pressure, serum albumin, hemoglobin, lean tissue index, fat tissue index and normalized protein nitrogen appearance. aP <0.01; bP =0.07
TABLE 4. Prognostic value of baseline volume status, variability of volume status and time-averaged volume status in different models considering patient survival and technique survival
|
Model 1 1
|
Model 2 2
|
Model 3 3
|
SHR
|
95% CI
|
P-value
|
SHR
|
95% CI
|
P-value
|
SHR
|
95% CI
|
P-value
|
Patient survival
|
|
|
|
Baseline RHI (per 1%)
|
1.03
|
1.004-1.053
|
0.02
|
-
|
-
|
-
|
|
|
|
Time-averaged RHI (per 1%)
|
-
|
-
|
-
|
1.05
|
1.03- 1.08
|
<0.0001
|
1.05
|
1.03- 1.08
|
<0.0001
|
VVS (per 1 unit)
|
-
|
-
|
-
|
-
|
-
|
-
|
0.96
|
0.79- 1.16
|
0.65
|
Modelχ2
|
48.7
|
86.1 a
|
85.7 b
|
Technique survival
|
|
|
|
Baseline RHI (per 1%)
|
1.03
|
1.002-1.048
|
0.03
|
-
|
-
|
-
|
|
|
|
Time-averaged RHI (per 1%)
|
-
|
-
|
-
|
1.04
|
1.01- 1.06
|
0.001
|
1.04
|
1.02- 1.06
|
0.001
|
|
|
|
|
|
|
|
|
|
|
VVS (per 1 unit)
|
-
|
-
|
-
|
-
|
-
|
-
|
0.99
|
0.83- 1.19
|
0.93
|
Modelχ2
|
50.0
|
66.0 c
|
65.9 d
|
1 Model 1 was adjusted for age, gender, baseline Charlson Comorbidity Index, baseline body mass index, baseline serum albumin, Kt/V and residual urine output
2 Model 2 was adjusted for age, gender, baseline Charlson Comorbidity Index, time-averaged body mass index, time-averaged serum albumin, Kt/V and residual urine output
3 Model 3 was adjusted for same variables of model 2 + VVS
a Patient survival: Model 2 vs. model 1 (P =0.0001)
b Patient survival: Model 3 vs. model 2 (P =0.6)
c Technique survival: Model 2 vs. model 1 (P =0.002)
d Technique survival: Model 3 vs. Model 2 (P =0.56)
Abbreviations: RHI, relative hydration index; SHR: subdistribution hazard ratio; VVS, variability in volume status