Effects of low-flux and high-flux hemodialysis on the survival of elderly maintenance hemodialysis patients

Figures & data

Figure 1. Flow diagram about the number of patients included and excluded from this study.

Table 1. Demographic characteristics and laboratory measurements before propensity score matching.

	High-flux group(n = 140)	Low-flux group(n = 219)	p
Demographic characteristics
Age (yr)	66.38 ± 5.224	70.19 ± 6.788	0.000
Sex (male; %)	77(55%)	100(45.7%)	0.084
Years on dialysis(yr)	2.97 ± 3.25	2.08 ± 2.89	0.009
Height (cm)	166.71 ± 8.484	163.56 ± 7.946	0.002
Weight (kg)	62.88 ± 12.269	59.71 ± 11.444	0.029
Body mass index (kg/m^2)	22.51 ± 3.41	22.29 ± 3.73	0.603
Current smokers, n (%)	23(16.4%)	39(18.7%)	0.593
Comorbidity
Diabetes, n (%)	50(35.7%)	90(41.1%)	0.333
Hypertension, n (%)	109(77.9%)	178(81.3%)	0.508
Cardiovascular disease, n (%)	70(50.0%)	149(68.03%)	0.001
Heart failure	27(38.6%)	60(40.3%)
Cardiac arrhythmia	36(51.4%)	79(53.0%)
Coronary artery disease	16(22.9%)	45(30.2%)
Peripheral vascular disease	17(24.3%)	23(15.4%)
Primary disease			0.018
Chronic glomerulonephritis, n (%)	40(28.6%)	37(16.9%)
Hypertensive renal damage, n (%)	29(20.7%)	52(23.7%)
diabetic nephropathy, n (%)	34(24.2%)	80(36.5%)
Other diseases, n (%)	37(26.4%)	50(22.8%)
Laboratory examination
Hemoglobin (g/L)	107.26 ± 16.34	104.98 ± 15.76	0.188
Albumin (g/L)	37.45 ± 3.55	36.42 ± 3.64	0.009
Calcium (mmol/L)	2.25 ± 0.21	2.21 ± 0.19	0.093
Phosphate (mmol/L)	1.88 ± 0.46	1.81 ± 0.57	0.243
intact parathyroid hormone (pg/mL)	361.68 ± 382.75	319.58 ± 356.59	0.316
blood urea nitrogen (mmol/L)	24.90 ± 5.29	23.77 ± 5.97	0.078
Creatinine (µmol/L)	932.56 ± 197.38	938.30 ± 211.91	0.804
uric acid (mmol/L)	440.30 ± 75.82	433.88 ± 71.05	0.440
β2-microglobulin (mg/L)	28.76 ± 6.47	31.75 ± 6.98	0.000
C-reactive protein (mg/dL)	5.75 ± 3.49	5.27 ± 2.88	0.172
Kt/V	1.33 ± 0.27	1.39 ± 0.23	0.108
Urea reduction ratio	76.53 ± 5.79	75.87 ± 5.99	0.302
Medication data
Vitamin D usage (%)	97(69.3%)	131(59.8%)	0.056
Phosphate binder usage (%)	110(78.6%)	156(71.2%)	0.095
ACEI or ARB usage (%)	67(47.9%)	107(48.9%)	0.853

Figure 2. All-cause and cardiovascular survival curves according to low-flux group and high-flux group according to Kaplan–Meier analysis. (a) K–M survival analysis revealed no significant difference in all-cause mortality between the high-flux group and the low-flux group (log-rank test, p = 0.559); (b) K–M survival analysis of cardiovascular mortality in the two groups: Patients in the low-flux subgroup had a greater death rate from cardiovascular mortality than did those in the high-flux subgroup (log-rank test, p = 0.049).

Table 2. Multivariate cox regression analysis of variables predicting mortality.

	All-cause mortality		Cardiovascular mortality
	HR (95% CI)	p value	HR (95% CI)	p value
Model 1 (demographics)	0.84(0.58–1.22)	0.372	0.60(0.38–0.94)	0.025
Model 2 (Model 1 + comorbidities and concomitant medications)	0.83(0.57–1.20)	0.320	0.59(0.38–0.93)	0.023
Model 3 (Model 2 + Laboratory examination)	0.79(0.54–1.16)	0.222	0.58(0.37–0.91)	0.019

Model 1 was adjusted for age, sex, and year on dialysis.

Model 2 was adjusted for Model 1, and comorbidities and concomitant medications included age, sex, year on dialysis, hypertension status, diabetes status, cardiovascular disease status, vitamin D usage, phosphate binder usage, and ACEI or ARB usage.

Model 3 was adjusted for Model 2 and laboratory examination results and included age, sex, year of dialysis, hypertension status, diabetes status, ­cardiovascular disease status, vitamin D usage, phosphate binder usage, ACEI or ARB usage, serum ALB concentration, hemoglobin, β2-microglobulin concentration and C-reactive protein.

Data availability statement

The datasets used in this study are available from the corresponding author upon reasonable request.