Benefits of Incremental Hemodialysis Seen in a Historical Cohort Study

Figures & data

Table 1 Baseline Characteristics of Incident Hemodialysis Patients by Hemodialysis Regimen

Characteristics	Incremental Group (N = 45)	Conventional Group (N = 68)	P
Age (years)	56.3 ± 14.3	61.9 ± 13.8	0.04
Male, n (%)	22 (48.9)	41 (60.3)	0.23
Body mass index (kg·m^−2)	22.1 ± 2.8	22.5 ± 3.9	0.64
Primary kidney disease			0.01
Diabetes, n (%)	4 (8.9)	25 (36.8)
Hypertension, n (%)	5 (11.1)	7 (10.3)
Glomerulonephritis, n (%)	25 (55.6)	21 (30.9)
Polycystic kidney disease, n (%)	6 (13.3)	6 (8.8)
Others/Unknown, n (%)	5 (11.1)	9 (13.2)
Comorbidity
Diabetes mellitus, n (%)	8 (17.8)	26 (38.2)	0.02
Cardiovascular disease, n (%)	6 (13.3)	15 (22.1)	0.24
Dialysis-related index
Urine output (mL/24h)	1566.2 ± 533.9	1129.4 ± 521.9	<0.001
eGFR (mL/min/1.73m^2)	6.71 (5.11, 8.97)	6.39 (4.72, 9.45)	0.90
Ultrafiltration (mL)	1268.3 ± 730.3	1975.6 ± 700.5	<0.001
Predialysis weight (kg)	60.7 ± 10.3	61.6 ± 13.6	0.71
SBP (mmHg)	131.3 ± 14.9	140.8 ± 16.0	0.002
DBP (mmHg)	76.4 ± 10.6	78.1 ± 10.6	0.42
Dialytic treatment time (hours/session)	3.98 ± 0.32	3.94 ± 0.12	0.31
spKt/V	1.35 ± 0.26	1.27 ± 0.33	0.13
URR	0.69 ± 0.07	0.65 ± 0.10	0.03
Laboratory measures
Albumin (g/dL)	4.02 ± 3.37	3.72 ± 4.35	<0.001
Hemoglobin (g/dL)	9.69 ± 1.11	9.54 ± 1.33	0.55
Calcium (mg/dL)	8.77 ± 0.91	8.79 ± 1.02	0.90
Phosphate (mg/dL)	4.85 ± 1.09	5.29 ± 1.68	0.13
iPTH (pg/mL)	204 (107, 336)	220 (119, 336)	0.85
CO2CP (mmol/L)	21.6 ± 4.2	21.5 ± 3.9	0.85
Potassium (mg/dL)	4.81 ± 0.75	4.67 ± 0.74	0.34
NT-proBNP (pg/mL)	1161 (733, 4021)	2867 (1124, 6196)	<0.001
Creatinine (mg/dL)	8.46 ± 2.12	8.20 ± 2.44	0.55
SUN (mg/dL)	77.2 ± 18.1	71.0 ± 18.8	0.09
C-reactive protein			0.20
<10 mg/dL (%)	43 (95.6)	59 (86.8)
≥10 mg/dL (%)	2 (4.4)	9 (13.2)

Notes: Continuous data presented as mean ± standard deviation or median (interquartile range); categorical data presented as number (percent).

Abbreviations: eGFR, estimated glomerular filtration rate; iPTH, intact parathyroid hormone; CO₂CP, carbon dioxide combining power; NT-proBNP, N-terminal pro–B-type natriuretic peptide; SUN, serum urea nitrogen; URR, urea reduction ratio.

Table 2 The Changes in Clinical and Laboratory Values Over the First Four Regularly Visits After Initiating Hemodialysis Therapy Among Patients with Incremental Hemodialysis

Characteristics	Q1 (n = 45)	Q2 (n = 45)	Q3 (n = 43)	Q4 (n = 41)	P for trend
Ultrafiltration (mL)	1278 (670, 1686)	1339 (752, 2314)	1771 (748, 2814)	1721 (826, 2375)	0.02
Predialysis weight (kg)	60.7 ± 10.3	61.5 ± 10.5	62.7 ± 10.4	62.3 ± 10.3	0.42
SBP (mmHg)	131.3 ± 14.9	131.5 ± 15.2	130.9 ± 14.6	132.9 ± 14.4	0.78
DBP (mmHg)	76.4 ± 10.6	76.3 ± 12.0	78.0 ± 12.1	77.2 ± 9.7	0.58
Dialytic treatment time (hours)	3.98 ± 0.32	4.04 ± 0.32	4.03 ± 0.37	4.00 ± 0.33	0.78
spKt/V	1.35 ± 0.26	1.35 ± 0.25	1.35 ± 0.25	1.38 ± 0.27	0.76
URR	0.69 ± 0.07	0.68 ± 0.07	0.68 ± 0.06	0.69 ± 0.07	0.97
Laboratory variables
Albumin (g/dL)	4.02 ± 0.34	4.04 ± 0.34	4.03 ± 0.34	4.06 ± 0.28	0.71
Hemoglobin (g/dL)	9.69 ± 1.11	10.64 ± 1.26	10.58 ± 1.39	10.32 ± 1.16	0.05
Calcium (mg/dL)	8.77 ± 0.91	9.05 ± 1.05	8.86 ± 1.01	9.06 ± 1.29	0.42
Phosphate (mg/dL)	4.85 ± 1.09	5.11 ± 1.45	5.15 ± 1.44	4.67 ± 1.53	0.63
iPTH (pg/mL)	204 (107, 336)	174 (64, 391)	181 (72, 302)	154 (93, 222)	0.07
CO2CP (mmol/L)	21.6 ± 4.2	20.8 ± 4.1	20.6 ± 3.2	21.7 ± 3.3	0.77
Potassium (mg/dL)	4.81 ± 0.75	4.69 ± 0.60	4.89 ± 0.72	4.74 ± 0.75	0.80
NT-proBNP (pg/mL)	1161 (733, 2595)	1100 (607, 1931)	1252 (738, 2183)	1454 (918, 3378)	0.17
Creatinine (mg/dL)	8.46 ± 2.12	9.29 ± 2.51	10.25 ± 3.08	10.15 ± 3.00	0.001
SUN (mg/dL)	77.2 ± 18.1	79.1 ± 16.5	84.9 ± 20.2	84.9 ± 20.2	0.36
C-reactive protein					0.24
<10 mg/dL (%)	43 (95.6)	44 (97.8)	41 (95.3)	37 (90.2)
≥10 mg/dL (%)	2 (4.4)	1 (2.2)	2 (4.7)	4 (9.8)

Notes: Continuous data presented as mean ± standard deviation or median (interquartile range); categorical data presented as number (percent). Q1–4, the first to fourth quarterly visits after hemodialysis initiation.

Abbreviations: eGFR, estimated glomerular filtration rate; iPTH, intact parathyroid hormone; CO₂CP, carbon dioxide combining power; NT-proBNP, N-terminal pro–B-type natriuretic peptide; SUN, serum urea nitrogen; URR, urea reduction ratio.

Table 3 Repeated-Measures Analysis of Changes in Laboratory Values and Blood Pressure Between Groups from Baseline to Post-Baseline Visits

	Second Visit		Third Visit		Fourth Visit
	Diff (95% CI)^a	P^b	Diff (95% CI)^a	P^b	Diff (95% CI)^a	P^b	P^c
Log-transformed NT-proBNP
Conventional group (n = 68)	0.10 (−0.09, 0.30)	0.44	−0.01 (−0.21, 0.19)	0.75	0.10 (−0.11, 0.30)	0.46	0.50
Incremental group (n = 45)	−0.02 (−0.26, 0.22)		0.04 (0.21, 0.29)		0.22 (−0.03, 0.47)
Systolic blood pressure
Conventional group (n = 68)	−2.82 (−5.84, 0.20)	0.22	−2.09 (−5.12, 0.95)	0.59	−3.09 (−6.23, 0.05)	0.07	0.30
Incremental group (n = 45)	0.20 (−3.51, 3.91)		−0.77 (−4.53, 2.99)		1.43 (−2.39, 5.25)
Diastolic blood pressure
Conventional group (n = 68)	−1.74 (−3.64, 0.16)	0.28	−1.31 (−3.22, 0.60)	0.08	−1.69 (−3.66, 0.28)	0.09	0.25
Incremental group (n = 45)	−0.08 (−2.41, 2.25)		1.45 (−0.92, 3.82)		1.03 (−1.37, 3.43)
Potassium
Conventional group (n = 68)	0.14 (−0.02, 0.31)	0.05	0.24 (0.07, 0.42)	0.23	0.18 (0.01, 0.35)	0.04	0.15
Incremental group (n = 45)	−0.12 (−0.32, 0.09)		0.08 (−0.13, 0.29)		−0.11 (−0.32, 0.10)
CO2CP
Conventional group (n = 68)	−0.49 (−0.52, 1.49)	0.10	−0.03 (−1.04, 0.98)	0.23	0.29 (−0.75, 1.33)	0.76	0.33
Incremental group (n = 45)	−0.85 (−2.08, 0.38)		−1.01 (−2.26, 0.25)		0.04 (−1.23, 1.30)
Hemoglobin
Conventional group (n = 68)	0.92 (0.51, 1.33)	0.92	1.10 (0.70, 1.51)	0.56	1.03 (0.61, 1.45)	0.23	0.55
Incremental group (n = 45)	0.95 (0.45, 1.45)		0.91 (0.40, 1.41)		0.63 (0.12, 1.14)
Calcium
Conventional group (n = 68)	0.33 (0.04, 0.62)	0.84	0.41 (0.12, 0.70)	0.20	0.26 (−0.04, 0.56)	0.89	0.48
Incremental group (n = 45)	0.28 (−0.07, 0.64)		0.11 (−0.25, 0.47)		0.29 (−0.07, 0.65)
Phosphate
Conventional group (n = 68)	−0.08 (−0.48, 0.33)	0.31	−0.08 (−0.49, 0.33)	0.31	0.10 (−0.33, 0.52)	0.32	0.15
Incremental group (n = 45)	0.26 (−0.24, 0.76)		0.26 (−0.25, 0.77)		−0.24 (−0.76, 0.28)
Log-transformed iPTH
Conventional group (n = 68)	−0.48 (−0.81, −0.15)	0.44	−0.46 (−0.79, −0.13)	0.32	−0.22 (−0.57, 0.12)	0.57	0.39
Incremental group (n = 45)	−0.27 (−0.68, 0.14)		−0.19 (−0.60, 0.22)		−0.38 (−0.80, 0.03)

Notes: ^aValues are adjusted least-squares means and 95% CI estimated from the mixed-effects model. ^bTest of significance of treatment group differences by visit (changes from baseline visit to the second visit, third visit or fourth visit between group) from the mixed-effects model. ^cTest of significance between treatment groups for the overall effect (group×visit) from the mixed-effects model.

Abbreviations: iPTH, intact parathyroid hormone; CO₂CP, carbon dioxide combining power; NT-proBNP, N-terminal pro–B-type natriuretic peptide.

Table 4 Unadjusted and Adjusted Hazard Ratio of RKF Loss by Hemodialysis Regimen

Model	Hazard Ratio	95% Confidential Interval	P
Univariate	0.23	0.11, 0.47	<0.001
Model 1	0.37	0.16, 0.82	0.01
Model 2	0.33	0.14, 0.82	0.02
Model 1 + UFV	0.45	0.20, 1.04	0.06
Model 2 + UFV	0.40	0.16, 1.05	0.06

Notes: Model 1, adjusted for age, sex, BMI, diabetes, urine output, eGFR, and systolic blood pressure at baseline; Model 2, adjusted for Model 1 plus NT-proBNP, albumin, and C-reactive protein at baseline.

Abbreviation: UFV, ultrafiltration volume at baseline.

Figure 1 Kaplan–Meier survival curve for (A) RKF loss, (B) the first arteriovenous access complication, (C) death; (D) the composite outcome of mortality and cardiovascular events. Numbers without parentheses in the risk table show the absolute numbers of patients at risk over time and numbers within parentheses show the absolute numbers of patients with events during a period.

Table 5 Unadjusted and Adjusted Hazard Ratio of Arteriovenous Access Complications by Hemodialysis Regimen

Model	Hazard Ratio	95% Confidential Interval	P
Cox Model
Univariate	0.36	0.13, 0.98	0.04
Model 1	0.27	0.09, 0.81	0.02
Model 2	0.26	0.08, 0.82	0.02
AG Model
Univariate	0.29	0.11, 0.79	0.02
Model 1	0.25	0.10, 0.63	0.003
Model 2	0.27	0.10, 0.74	0.01
PWP-TT Model
Univariate	0.37	0.16, 0.86	0.02
Model 1	0.30	0.14, 0.66	0.003
Model 2	0.31	0.12, 0.80	0.02

Notes: Model 1, adjusted for age, sex, BMI, diabetes, urine output, eGFR, and systolic blood pressure at baseline; Model 2, adjusted for Model 1 plus NT-proBNP, albumin, and C-reactive protein at baseline.

Abbreviations: AG Model, Andersen and Gill Cox model; PWP-TT Model, Prentice, Williams and Peterson-Total Time Model.

Table 6 Unadjusted and Adjusted Hazard Ratio of the Death and the Composite Outcome of All-Cause Mortality and Cardiovascular Events by Hemodialysis Regimen

Model	Hazard Ratio	95% Confidential Interval	P
Composite Outcome
Univariate	0.41	0.13, 1.24	0.11
Model 1	0.80	0.23, 2.80	0.72
Model 2	0.88	0.23, 3.43	0.85
Death
Univariate	0.30	0.04, 2.59	0.28
Model 1	0.96	0.08, 12.02	0.99
Model 2	1.83	0.06, 52.25	0.72

Notes: Model 1, adjusted for age, sex, BMI, diabetes, urine output, eGFR, and systolic blood pressure at baseline; Model 2, adjusted for Model 1 plus NT-proBNP, albumin, and C-reactive protein at baseline.