Association of frequent intradialytic hypotension with the clinical outcomes of patients on hemodialysis: a prospective cohort study

Figures & data

Figure 1. CONSORT diagram.

Table 1. Baseline characteristics of hemodialysis patients in IDH frequent/infrequent groups by Definition 1 and Definition 2.

Characteristics	All (n = 163)	Definition 1			Definition 2
		IDH infrequent (n = 115)	IDH frequent (n = 48)	P value	IDH infrequent (n = 118)	IDH frequent (n = 45)	P value
Male	103 (63.19%)	81 (70.43%)	22 (45.83%)	0.003	83 (70.34%)	20 (44.44%)	0.002
Age, years	62.1 ± 11.4	61.3 ± 11.2	64.0 ± 11.7	0.185	61.4 ± 11.2	63.9 ± 11.8	0.225
Vintage, months	53 (26,88)	50 (25,88)	59 (30,90)	0.320	51 (25,88)	59 (31,85)	0.345
DM	38 (23.31%)	23 (20%)	15 (31.25%)	0.122	25 (21.19%)	13 (28.89%)	0.298
CVD history	41 (25.15%)	32 (27.83%)	9 (18.75%)	0.223	32 (27.12%)	9 (20%)	0.349
History of taking medication for hypertension	105 (64.42%)	85 (73.91%)	20 (41.67%)	0.000	87 (73.73%)	18 (40%)	<0.001
History of statin use	32 (19.63%)	23 (20%)	9 (18.75%)	0.855	23 (19.49%)	9 (20%)	0.942
Residual renal function	40 (24.54%)	31 (26.96%)	9 (18.75%)	0.267	32 (27.12%)	9 (17.78%)	0.215
BMI, kg/m^2	21.44 (19.64,23.52)	21.44 (19.64,23.54)	21.43 (19.55,23.51)	0.823	21.45 (19.65,23.62)	21.21 (19.39,23.22)	0.475
N_UF, %	3.89 ± 1.22	3.78 ± 1.30	4.15 ± 0.98	0.050	3.79 ± 1.29	4.13 ± 1.01	0.085
pre_SBP, mmHg	141.1 ± 18.5	144.3 ± 14.7	133.5 ± 23.8	0.005	144.3 ± 15.0	132.8 ± 23.8	0.004
pre_DBP, mmHg	78.9 ± 10.0	80.3 ± 8.7	75.6 ± 12.1	0.017	80.3 ± 8.7	75.4 ± 12.3	0.018
Kt/V	1.32 (1.19,1.54)	1.31 (1.15,1.50)	1.40 (1.21,1.57)	0.186	1.31 (1.15,1.50)	1.41 (1.22,1.57)	0.102
GNRI	102.53 (97.90,105.89)	102.85 (97.90,106.17)	101.72 (97.50,104.62)	0.351	102.95 (97.90,106.17)	101.63 (97.91,104.44)	0.255
NT-proBNP, ng/L	4403 (1732,10310)	4223 (1520,9044)	4453 (2265,12241)	0.546	4246 (1520,9044)	4460 (2322,12147)	0.588
TnT, μg/L	0.046 (0.031,0.076)	0.043 (0.030,0.075)	0.056 (0.036,0.098)	0.086	0.043 (0.030,0.076)	0.054 (0.036,0.091)	0.207
CRP, mg/L	2.55 (0.95,6.58)	2.36 (0.93,6.13)	4.14 (1.19,8.28)	0.230	2.39 (0.94,6.31)	3.96 (1.23,8.42)	0.286
iPTH, pg/ml	283.1 (156.6,489.8)	256.9 (132.6,464.1)	343.2 (194.0,557.5)	0.021	251.0 (132.6,464.1)	357.1 (228.5,548.0)	0.016
CAP, mg/dL	55.73 (45.38,68.3)	54.96 (43.87,65.74)	59.05 (48.40,72.95)	0.101	55.23 (44.30,66.25)	58.33 (48.13,73.01)	0.182
Hb, g/L	109 (100,115)	109 (100,115)	109 (100,114)	0.876	109 (100,115)	111 (101,114)	0.649
Alb, g/L	42.1 (40.1,44.5)	42.4 (40.0,44.6)	41.5 (40.3,43.7)	0.184	42.4 (40.0,44.6)	41.5 (40.4,43.6)	0.181
Ferritin, μg/L	239.2 (119.3,426.2)	222.4 (118.8,450.2)	252.2 (123.6,426.2)	0.543	235.5 (118.8,450.2)	263.2 (126.2,425.2)	0.508
CHO, mmol/L	4.13 (3.44,4.93)	4.04 (3.36,4.79)	4.52 (3.94,5.07)	0.020	4.05 (3.37,4.81)	4.52 (3.98,5.08)	0.025
LDL, mmol/L	2.48 (1.87,3.15)	2.35 (1.76,3.09)	2.60 (2.28,3.27)	0.010	2.35 (1.76,3.09)	2.64 (2.33,3.27)	0.008
SCI, mg/kg/d	21.64 ± 2.75	21.72 ± 2.72	21.46 ± 2.86	0.605	21.75 ± 2.79	21.37 ± 2.67	0.429

IDH: intradialytic hypotension; DM: diabetes mellitus; CVD: cardiovascular disease; BMI: body mass index; N_UF: net ultrafiltration %; SBP: systolic blood pressure; DBP: diastolic blood pressure; Kt/V: urea clearance index; GNRI: Geriatric Nutritional Risk Index; NT-proBNP: N-terminal pro-B-type natriuretic peptide; TnT:Troponin T; CRP: C-reactive protein; iPTH: intact parathyroid hormone; CAP: Calcium and phosphorus product; Hb: Hemoglobin; Alb: Albumin; CHO: cholesterol; LDL: low-density lipoprotein cholesterol; SCI: simplified Creatinine Index.

Definition 1 of IDH: for patients with pre-dialysis SBP <159 mmHg, nadir SBP <90 mmHg during hemodialysis; for patients with pre-dialysis SBP ≥160 mmHg, nadir SBP <100 mmHg during hemodialysis.

Definition 2 of IDH: nadir SBP <90 mmHg during dialysis.

Figure 2. Kaplan-Meier curves of all-cause mortality between IDH frequent and IDH infrequent group according to (A) Definition 1, (B) Definition 2; cardiovascular mortality between the frequent and infrequent IDH groups according to (C) Definition 1, (D) Definition 2; and primary all-cause hospitalization event between IDH frequent and IDH infrequent group according to (E) Definition 1, (F) Definition 2.

Table 2. Outcomes of hemodialysis patients in IDH frequent/infrequent groups by Definition 1 and Definition 2.

Characteristics		Definition 1		P	Definition 2		P
36-month outcomes, n (%)	All (n = 163)	IDH infrequent (n = 115)	IDH frequent (n = 48)		IDH infrequent (n = 118)	IDH frequent (n = 45)
All-cause hospitalization	105 (64.42%)	69 (60.0%)	36 (75.0%)	0.068	72 (61.02%)	33 (73.33%)	0.142
Death	37 (22.7%)	19 (16.52%)	18 (37.5%)	0.004	21 (17.80%)	16 (35.56%)	0.016
Cardiovascular Events	39 (23.93%)	25 (21.74%)	14 (29.17%)	0.311	26 (22.03%)	13 (28.89%)	0.359
Cardiovascular Death	17 (10.43%)	8 (6.96%)	9 (18.75%)	0.025	10 (8.47%)	7 (15.56%)	0.186
Vascular Access Events	48 (29.45%)	33 (28.7%)	15 (31.25%)	0.744	34 (28.81%)	14 (34.04%)	0.774

Table 3. Univariable and multivariable Cox regression analyses of all-cause mortality.

Variables	Univariable analysis		Multivariable analysis (model 1)		Multivariable analysis (model 2)
	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Frequent IDH (Definition 1)	2.659 (1.395–5.070)	0.003	2.553 (1.334–4.886)	0.005	–	–
Frequent IDH (Definition 2)	2.328 (1.214–4.462)	0.011	–	–	2.406 (1.253–4.621)	0.008
Dialysis vintage	0.996 (0.990–1.003)	0.301
DM	3.157 (1.645–6.057)	0.001	2.271 (1.150–4.483)	0.018	2.397 (1.221–4.705)	0.011
CVD history	0.810 (0.370–1.771)	0.597
History of taking medication for hypertension	0.970 (0.494–1.905)	0.930
History of statin use	1.364 (0.643–2.890)	0.418
Residual renal function	0.664 (0.292–1.512)	0.329
N_UF	1.112 (0.850–1.454)	0.438
Pre-SBP	1.012 (0.993–1.031)	0.206
Pre-DBP	1.014 (0.980–1.049)	0.429
Nt-proBNP	1.000059 (1.000034–1.000084)	<0.001	1.000051 (1.000025–1.000077)	<0.001	1.00052 (1.00026–1.00078)	<0.001
Troponin T	5.284 (0.647–43.126)	0.120
CRP	1.004 (0.995–1.012)	0.407
iPTH	1.000 (1.000–1.001)	0.234
Calcium and phosphorus product	1.000 (0.983–1.017)	0.984
Hemoglobin	0.993 (0.972–1.014)	0.490
Ferritin	1.000 (0.999–1.001)	0.783
Total cholesterol	1.101 (0.835–1.450)	0.496
LDL	1.251 (0.926–1.689)	0.145
GNRI	0.939 (0.894–0.986)	0.012
SCI	0.830 (0.730–0.944)	0.004

IDH: intradialytic hypotension; DM: diabetes mellitus; CVD: cardiovascular disease; BMI: body mass index; ESRD: end-stage renal disease; IDWG%: the proportion of weight gain during dialysis interval; N_UF: net ultrafiltration %; SBP: systolic blood pressure; DBP: diastolic blood pressure; Kt/V: urea clearance index; GNRI: Geriatric Nutritional Risk Index; NT-proBNP: N-terminal pro-B-type natriuretic peptide; TnT:Troponin T; CRP: C-reactive protein; iPTH: intact parathyroid hormone; CAP: Calcium and phosphorus product; Hb: Hemoglobin; Alb: Albumin; CHO: cholesterol; LDL: low-density lipoprotein cholesterol; AVFSCI: simplified Creatinine Index.

Definition 1 of IDH: for patients with pre-dialysis SBP <159 mmHg, nadir SBP <90 mmHg during hemodialysis; for patients with pre-dialysis SBP ≥160 mmHg, nadir SBP <100 mmHg during hemodialysis.

Definition 2 of IDH: nadir SBP <90 mmHg during dialysis.

Table 4. Univariable and multivariable Cox regression analyses of cardiovascular mortality.

Variables	Univariable analysis		Multivariable analysis (model 1)		Multivariable analysis (model 2)
	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Frequent IDH (Definition 1)	2.917 (1.125–7.561)	0.028
Frequent IDH (Definition 2)	1.963 (0.747–5.157)	0.171
Dialysis vintage	0.995 (0.985–1.006)	0.374
DM	5.278 (2.008–13.875)	0.001	5.278 (2.008–13.875)	0.001	5.278 (2.008–13.875)	0.001
CVD history	0.914 (0.298–2.802)	0.874
History of taking medication for hypertension	0.994 (0.368–2.688)	0.991
History of statin use	1.786 (0.629–5.071)	0.276
Residual renal function	0.908 (0.296–2.786)	0.866
N_UF	1.146 (0.769–1.706)	0.503
Pre-SBP	1.000 (0.974–1.026)	0.993
Pre-DBP	0.990 (0.943–1.040)	0.690
Nt-proBNP	1.000047 (1.000011–1.000084)	0.012
Troponin T	0.454 (0.001–276.315)	0.809
CRP	0.987 (0.937–1.039)	0.618
iPTH	1.000 (0.999–1.001)	0.443
Calcium and phosphorus product	0.995 (0.969–1.021)	0.677
Hemoglobin	0.978 (0.950–1.008)	0.153
Ferritin	1.001 (1.000–1.002)	0.195
Total cholesterol	1.279 (0.903–1.812)	0.165
LDL	1.363 0.918–2.025)	0.125
GNRI	0.974 (0.913–1.039)	0.429
SCI	0.784 (0.648–0.948)	0.012

IDH: intradialytic hypotension; DM: diabetes mellitus; CVD: cardiovascular disease; BMI: body mass index; ESRD: end-stage renal disease; IDWG%: the proportion of weight gain during dialysis interval; N_UF: net ultrafiltration%; SBP: systolic blood pressure; DBP: diastolic blood pressure; Kt/V: urea clearance index; GNRI: Geriatric Nutritional Risk Index; NT-proBNP: N-terminal pro-B-type natriuretic peptide; TnT:Troponin T; CRP: C-reactive protein; iPTH: intact parathyroid hormone; CAP: Calcium and phosphorus product; Hb: Hemoglobin; Alb: Albumin; CHO: cholesterol; LDL: low-density lipoprotein cholesterol; AVFSCI: simplified Creatinine Index.

Definition 1 of IDH: for patients with pre-dialysis SBP <159 mmHg, nadir SBP <90 mmHg during hemodialysis; for patients with pre-dialysis SBP ≥160 mmHg, nadir SBP <100 mmHg during hemodialysis.

Definition 2 of IDH: nadir SBP <90 mmHg during dialysis.

Table 5. Univariable and multivariable Cox regression analyses of all-cause hospitalization.

Variables	Univariable analysis		Multivariable analysis (model 1)		Multivariable analysis (model 2)
	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Frequent IDH (Definition 1)	1.429 (0.954–2.139)	0.083	1.361 (0.897–2.064)	0.147
Frequent IDH (Definition 2)	1.371 (0.907–2.071)	0.134			1.303 (0.852–1.993)	0.222
Dialysis vintage	1.000 (0.997–1.004)	0.811
Body mass index	0.972 (0.917–1.030)	0.339
DM	1.551 (1.015–2.370)	0.042	1.082 (0.675–1.733)	0.476	1.104 (0.690–1.767)	0.681
CVD history	1.523 (1.005–2.310)	0.048	1.196 (0.760–1.880)	0.439	1.183 (0.753–1.858)	0.467
History of taking medication for hypertension	1.185 (0.790–1.779)	0.412
History of statin use	1.735 (1.113–2.705)	0.015	1.688 (1.031–2.763)	0.037	1.676 (1.023–2.745)	0.040
Residual renal function	0.888 (0.567–1.391)	0.604
N-UF	1.068 (0.915–1.245)	0.405
Pre-SBP	1.009 (0.998–1.021)	0.101
Pre-DBP	0.998 (0.979–1.018)	0.874
Kt/V	0.872 (0.467–1.629)	0.668
Nt-proBNP	1.000028 (1.000009–1.000046)	0.003	1.00002 (1.00000–1.00004)	0.059	1.00002 (1.00000–1.00004)	0.065
Troponin T	1.986 (0.427–9.228)	0.381
CRP	1.013 (1.006–1.019)	0.000	1.010 (1.003–1.018)	0.006	1.011 (1.003–1.018)	0.006
iPTH	1.000 (1.000–1.001)	0.130
Calcium and phosphorus product	0.999 (0.989–1.009)	0.870
Hemoglobin	1.001 (0.988–1.013)	0.909
Albumin	0.950 (0.895–1.007)	0.085	0.974 (0.915–1.036)	0.403	0.973 (0.914–1.035)	0.384
Ferritin	1.000 (1.000–1.001)	0.295
Total cholesterol	0.998 (0.837–1.189)	0.981
LDL	1.095 (0.884–1.357)	0.404
GNRI	0.983 (0,952–1.015)	0.305
SCI	0.916 (0.852–0.986)	0.019	0.937 (0.870–1.009)	0.085	0.937 (0.870–1.010)	0.089

IDH: intradialytic hypotension; DM: diabetes mellitus; CVD: cardiovascular disease; BMI: body mass index; ESRD: end-stage renal disease; IDWG%: the proportion of weight gain during dialysis interval; N_UF: net ultrafiltration%; SBP: systolic blood pressure; DBP: diastolic blood pressure; Kt/V: urea clearance index; GNRI: Geriatric Nutritional Risk Index; NT-proBNP: N-terminal pro-B-type natriuretic peptide; TnT:Troponin T; CRP: C-reactive protein; iPTH: intact parathyroid hormone; CAP: Calcium and phosphorus product; Hb: Hemoglobin; Alb: Albumin; CHO: cholesterol; LDL: low-density lipoprotein cholesterol; AVFSCI: simplified Creatinine Index.

Definition 1 of IDH: for patients with pre-dialysis SBP <159 mmHg, nadir SBP <90 mmHg during hemodialysis; for patients with pre-dialysis SBP ≥160 mmHg, nadir SBP <100 mmHg during hemodialysis.

Definition 2 of IDH: nadir SBP <90 mmHg during dialysis.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.