Heart rate variability predicts mortality in peritoneal dialysis patients

Figures & data

Table 1. Demographic characteristics of the study population.

Variable	Result
Number of patients	81
Number of males (%)	41 (50.61)
Age (years)	65.25 ± 11.97
Time on PD (months)	14 (range 3–99)
Primary disease, n (%)
Glomerulonephritis	22 (27.16)
Diabetic nephropathy	23 (28.40)
Hypertensive nephropathy	13 (16.05)
Interstitial nephritis	13 (16.05)
Polycystic kidney disease	2 (2.47)
Other or unknown	8 (9.88)
Diabetes, n (%)	26 (32.10)
Protein–energy wasting, n (%)	13 (18.31)

Table 2. Clinical features of patients grouped by survival status.

	Survival (n = 56)	Non-survival (n = 25)	p
Age (years)	60.04 ± 12.23	68.52 ± 9.03	0.004
Male, n (%)	30 (30/56)	11 (11/26)	0.426
BMI	23.83 ± 3.97	24.80 ± 3.05	0.298
Time on PD (months)	21.15 ± 16.62	20.63 ± 25.87	0.915
Diabetes, n (%)	17 (17/56)	9 (9/25)	0.415
Hypertension, n (%)	28 (28/52)	12 (12/23)	0.894
SBP	136.15 ± 24.84	132.52 ± 26.87	0.571
DBP	82.65 ± 13.15	73.91 ± 11.67	0.008
Hemoglobin (g/L)	115.92 ± 19.25	113.57 ± 21.68	0.638
BUN (mmol/L)	21.15 ± 5.49	18.90 ± 5.96	0.106
Creatinine (mmol/L)	853.02 ± 264.87	779.43 ± 218.02	0.232
Albumin (g/L)	38.22 ± 4.13	36.83 ± 3.55	0.164
Serum potassium (mmol/L)	4.46 ± 0.79	4.04 ± 0.97	0.048
hs-CRP (mg/L)	1.07 ± 0.982	6.66 ± 17.58	0.056
PTH (pg/mL)	206.29 ± 181.54	204.98 ± 222.64	0.919
PEW, n (%)	9 (9/49)	4 (4/22)	0.606
HDL cholesterol (mg/dL)	1.24 ± 0.401	1.20 ± 0.35	0.709
LDL cholesterol (mg/dL)	3.02 ± 0.95	3.44 ± 1.45	0.173
Triglycerides (mg/dL)	2.36 ± 1.43	2.74 ± 2.12	0.394
Urine volume (mL/day)	609.41 ± 492.35	231.43 ± 308.37	0.000
UF(mL/day)	424.98 ± 310.15	595.00 ± 391.32	0.061
TFR (mL/day)	1019.35 ± 377.48	868.96 ± 396.33	0.113
GFR (mL/min)	2.25 ± 2.10	1.26 ± 1.70	0.047
rKt/V	0.58 ± 0.50	0.27 ± 0.35	0.002
pKt/V	1.32 ± 0.43	1.49 ± 0.41	0.067
tKt/V	1.91 ± 0.48	1.80 ± 0.47	0.381
ECW (L)	15.67 ± 3.58	15.12 ± 3.51	0.525
ICW (L)	13.17 ± 4.04	11.04 ± 3.81	0.029
TBW (L)	29.06 ± 6.95	26.16 ± 6.92	0.088
ACEI, n (%)	15 (37.5)	3 (21.4)	0.272
Beta-blocker, n (%)	26 (40.5)	8 (23.8)	0.600

Notes: BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; hs-CRP, high-sensitivity C-reactive protein; PEW, protein–energy wasting; PTH, parathyroid hormone; HDL, high density lipoprotein; LDL, low density lipoprotein; UF, ultrafiltration; TFR, total fluid removal; GFR, glomerular filtration rate; pKt/V, peritoneal Kt/V; rKt/V, renal Kt/V; tKt/V; total Kt/V (rKt/V + pKt/V); ECW, extracellular water; ICW, intracellular water; TBW, total body water; ACEI, angiotensin converting enzyme inhibitors.

Table 3. HRV measures of patients grouped by survival status.

	Survival (n = 56)	Non-survival (n = 25)	p
SDNN (ms)	36.12 ± 39.77	57.44 ± 48.43	0.061
rMSSD (ms)	36.12 ± 39.77	57.44 ± 48.43	0.046
SDSD (ms)	56.55 ± 78.05	104.72 ± 104.16	0.046
pNN50	11.12 ± 21.75	13.00 ± 21.97	0.721
TP power (ms2)	1826.09 ± 4944.06	2996.92 ± 3776.97	0.295
VLF (ms2)	379.27 ± 698.52	433.40 ± 551.27	0.733
LF (ms2)	499.41 ± 1415.07	588.76 ± 821.43	0.770
LFnor power (nu)	54.12 ± 23.64	36.48 ± 21.03	0.001
HF power (ms2)	715.68 ± 2297.69	1372.28 ± 1879.91	0.214
HFnor power (nu)	30.75 ± 14.83	41.68 ± 13.93	0.003
LF/HF	2.82 ± 2.77	1.21 ± 1.19	0.000

Notes: SDNN, SD of all normal-to-normal NN intervals; rMSSD, the square root of the mean of the squared differences between adjacent normal NN intervals; SDSD, the SD of differences between adjacent NN intervals; pNN50, the percentage of differences between adjacent normal NN intervals that were >50 ms computed; TP, total power; VLF, very low frequency; LF, low frequency; HF, high frequency.

Table 4. Univariate Cox regression analysis of clinical characteristics related to death.

	RR (95% CI)	p
Age (per 1 year increase)	1.061 (1.016–1.109)	0.007
Male versus female	1.504 (0.650–3.479)	0.340
Diabetes versus non-diabetes	1.558 (0.673–3.610)	0.301
PEW (by SGA) versus no PEW	1.412 (0.471–4.223)	0.538
Potassium (per 1 mmol/L increase)	0.501 (0.270–0.900)	0.021
Serum albumin (per 1 g/L increase)	0.928 (0.843–1.022)	0.128
serum urea (per 1 mmol/L increase)	0.924 (0.811–1.007)	0.070
Hemoglobin (per 1 g/L increase)	0.996 (0.975–1.017)	0.695
Beta-blocker versus no beta-blocker	0.441 (0.146–1.331)	0.146
ACEI versus no ACEI	0.781 (0.521–1.233)	0.272
SBP (per 1 mmHg increase)	0.994 (0.977–1.011)	0.492
DBP (per 1 mmHg increase)	0.952 (0.920–0.985)	0.070
ICW (per 1 L increase)	0.880 (0.786–0.986)	0.028
Urine volume (per 1 mL increase)	0.998 (0.996–0.999)	0.004
rKt/V (per 1 increase)	0.195 (0.057–0.675)	0.010
PTH (per 1 pg/mL increase)	1.000 (0.997–1.002)	0.769
hs-CRP (per 1 mg/L increase)	1.054 (1.023–1.085)	0.000

Notes: PEW, protein–energy wasting; ACEI, angiotensin converting enzyme inhibitors; SBP, systolic blood pressure; DBP, diastolic blood pressure; ICW, intracellular water; rKt/V, renal Kt/V; PTH, parathyroid hormone; hs-CRP, high-sensitivity C-reactive protein.

Table 5. Univariate Cox regression analysis of heart rate variability measures in relation to death.

	RR (95% CI)	p
SDNN (per 1 ms increase)	1.007 (1.000–1.014)	0.060
rMSSD (per 1 ms increase)	1.005 (1.000–1.010)	0.039
SDSD (per 1 ms increase)	1.004 (1.000–1.007)	0.039
TP (per 1 ms^2 increase)	1.162 (0.903–1.496)	0.244
LF (per 1 ms^2 increase)	1.005 (0.794–1.273)	0.966
LF norm (per 1 nu increase)	0.977 (0.961–0.993)	0.004
HF (per 1 ms^2 increase)	1.122 (0.936–1.346)	0.213
HF norm (per 1 nu increase)	1.148 (0.851–1.549)	0.366
LF/HF (per 1 increase)	0.685 (0.496–0.947)	0.022

Notes: SDNN, SD of all normal-to-normal NN intervals; rMSSD, the square root of the mean of the squared differences between adjacent normal NN intervals; SDSD, the SD of differences between adjacent NN intervals; pNN50, the percentage of differences between adjacent normal NN intervals that were >50 ms computed; TP, total power; VLF, very low frequency; LF, low frequency; HF, high frequency.

Figure 1. Kaplan–Meier survival curves for death in patients dichotomized by the median values of LF/HF. LF, low frequency; HF, high frequency.

Figure 2. Kaplan–Meier survival curves for cardiac death in patients with a urine volume of >100 versus ≤100 mL/L.

Figure 3. Kaplan–Meier survival curves for death in patients with a hs-CRP >3 mg/L versus ≤3 mg/L. hs-CRP, high-sensitivity C-reactive protein.

Table 6. Multivariate Cox regression analysis of clinical and HRV measures in relation to death.

	All-cause death RR (95% CI)	p
Age (per 1 year increase)	1.054 (1.009–1.101)	0.012
hs-CRP (per 1 mg/L increase)	1.035 (1.009–1.061)	0.010
Urine volume (per 1 mL increase)	0.998 (0.997–1.000)	0.024
LF/HF (per 1 increase)	0.701 (0.501–0.979)	0.028

Notes: hs-CRP, high-sensitivity C-reactive protein; LF, low frequency; HF, high frequency.

Nakai S, Iseki K, Itami N, et al. Overview of regular dialysis treatment in Japan (as of 31 December 2009). Ther Apher Dial. 2012;16:11–53

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