Correlation between ultrafiltration rate and hemoglobin level and erythropoietin response in hemodialysis patients

Figures & data

Figure 1. Flow diagram of the patient selection.

Table 1. Baseline demographics and clinical characteristics among groups according to ultrafiltration rate.

	UFR < 10ml/h/kg (N = 107)	UFR 10–13ml/h/kg (N = 91)	UFR > 13ml/h/kg (N = 27)	P
UFR (ml/h/kg)	8.3 (7.2, 9.4)	11.31 (10.5, 11.8)	13.96 (13.4, 14.8)	<0.001*†^‡
Male (n, %)	67 (62.6%)	64 (70.3%)	12 (44.4%)	0.047*
Age (years)	60 (51, 66)	49 (42, 59)	51 (34, 63)	<0.001†^‡
Dry weight (kg)	68.5 (61.9, 75.7)	65.1 (56.6, 73.9)	54 (49.5, 59.5)	<0.001*†
BMI (kg/m2)	24.71 (22.4, 26.9)	22.91 (21.3, 25.4)	20.28 (19.7, 21.7)	<0.001*†^‡
Dialysis ages (months)	42 (20, 77)	35 (16, 70)	42 (12, 74)	0.468
Monthly EPO doses/weight (IU/kg)	629 (513, 797)	678 (541, 893)	940 (711, 1122)	<0.001*†
ERI (IU/kg/w/g/L)	1.5 (1.13, 1.85)	1.5 (1.17, 2.19)	2.29 (1.63, 3.21)	<0.001*†
Primary etiology				0.667
Chronic glomerulonephritis	40 (37.4%)	45 (49.5%)	14 (51.9%)
Diabetes mellitus	36 (33.6%)	26 (28.6%)	8 (29.6%)
Hypertension	10 (9.3%)	7 (7.7%)	2 (7.4%)
Others	21 (19.6%)	13 (14.3%)	3 (11.1%)

Notes: BMI: body mass index; UFR: ultrafiltration rate; ERI: EPO resistance index; P value shows overall differences among three groups, *represents a statistically significant difference between UFR >13 mL/h/kg and UFR 10–13 mL/h/kg group; †represents a statistically significant difference between UFR >13 mL/h/kg and UFR <10 mL/h/kg group; ‡represents a statistically significant difference between UFR 10-13 mL/h/kg and UFR <10 mL/h/kg group.

Table 2. Biochemical characteristics among groups according to ultrafiltration rate.

	UFR < 10ml/h/kg (N = 107)	UFR 10–13ml/h/kg (N = 91)	UFR > 13ml/h/kg (N = 27)	P
RBC (10^12/L)	3.76 (3.4, 4.0)	3.8 (3.4, 4.0)	3.42 (3.2, 3.8)	0.014*†
Hemoglobin (g/L)	108 (101, 116.0)	111 (102, 117)	99 (93, 110)	0.001*†
Hematocrit (%)	34 (31.6, 35.8)	34 (31.2, 36.4)	30.6 (27.9, 34.4)	0.006*†
Potassium (mmol/L)	5.16 (4.7, 5.6)	5.49 (4.9, 6.1)	4.9 (4.3, 6.0)	0.015†
Calcium (mmol/L)	2.20 (2.1, 2.3)	2.19 (2.1, 2.3)	2.17 (2.1, 2.3)	0.802
Phosphorus (mmol/L)	2.23 (1.8, 2.7)	2.32 (1.9, 2.8)	2.07 (1.5, 2.5)	0.131
PTH (pg/ml)	201.6 (109, 357)	232.05 (142, 302)	201 (121, 329)	0.782
Albumin (g/L)	39.9 (37.9, 41.8)	40 (38.7, 42.8)	38.1 (36.8, 41.4)	0.056
KT/V	1.23 (1.1, 1.4)	1.29 (1.1, 1.5)	1.49 (1.3, 1.6)	0.002*†
Ferritin (ng/ml)	52.21 (26.0, 98.6)	47.46 (24.6, 104.7)	54.21 (21.7, 127.7)	0.993
C-reactive protein(mg/L)	1.23 (0.9, 2.4)	1.115 (0.7, 1.8)	1.07 (0.7, 3.0)	0.058
URR (%)	65.7 (60, 70)	65.6 (60, 70)	71.0 (66, 75)	0.064

Notes: Kt/v: urea nitrogen clearance index; URR: urea reduction ratio; RBC: red blood cell; P value shows overall differences among three groups, *represents a statistically significant difference between UFR >13 mL/h/kg and UFR 10–13 mL/h/kg group; †represents a statistically significant difference between UFR >13 mL/h/kg and UFR <10 mL/h/kg group; ^‡represents a statistically significant difference between UFR 10–13 mL/h/kg and UFR <10 mL/h/kg group.

Table 3. Multiple linear correlations between hemoglobin and other clinical parameters.

	R2	P
Male	0.233	<0.001
Dry weight	0.184	0.006
UFR	−0.169	0.011
Calcium	0.270	<0.001
Phosphorus	0.142	0.034
Albumin	0.332	<0.001
C-reactive protein	−0.195	0.003

Note: UFR: urea reduction ratio.

Table 4. Multivariate logistic regression analyses of related factors for hemoglobin.

	OR	95%CI	P
Male	0.180	0.957, 7.378	0.011
Dry weight	0.011	−0.116, 0.136	0.872
UFR	−0.158	−1.334, −0.147	0.015
Calcium	0.216	6.789, 24.624	0.001
Phosphorus	0.088	−0.609, 3.815	0.155
Albumin	0.179	0.137, 1.227	0.014
C-reactive protein	−0.097	−0.833, 0.132	0.154

Note: UFR: ultrafiltration rate.

Table 5. Prognostic value of UFR.

	UFR < 10ml/h/kg (N = 97)	UFR 10–13ml/h/kg (N = 81)	UFR > 13ml/h/kg (N = 21)	P
Average number of hospitalizations	0.98	0.47	1.1	0.036^‡
Average number of emergency Department visits	0.61	0.40	1.24	0.228
Number of deaths (n, %)	11(11.3%)	7(8.6%)	3(12%)	0.807

Note: P value shows overall differences among the three groups, ^‡represents a statistically significant difference between UF 10–13 mL/h/kg and UF <10 mL/h/kg group.

Data availability statement

This published article and its Online Resources include all the data generated or analyzed during this study.