Table 4.

Unadjusted and adjusted HRs of HRV measures for mortality risk

Predictor	Unit	Unadjusted		Adjusteda
		HR (95% CI)b	P	HR (95% CI)b	P
SDNN	−25 ms	1.30 (1.09–1.55)	0.004	1.08 (0.90–1.30)	0.42
SDANN	−25 ms	1.32 (1.09–1.59)	0.004	1.09 (0.89–1.33)	0.40
RMSSD	−1.5 ms	1.00 (0.96–1.03)	0.89	1.00 (0.97–1.04)	0.78
pNN50	−1.5 ms	0.99 (0.92–1.05)	0.64	1.02 (0.95–1.09)	0.63
HRVTI	−10	1.24 (1.10–1.40)	<0.001c	1.14 (0.85–1.52)	0.39
ULF	−0.5 ln (ms2)	1.24 (1.10–1.40)	<0.001c	1.09 (0.95–1.25)	0.21
VLF	−0.5 ln (ms2)	1.18 (1.08–1.29)	<0.001c	1.07 (0.96–1.18)	0.22
LF	−5 ln (ms2)	3.55 (1.63–7.70)	0.001c	1.83 (0.77–4.31)	0.16
HF	−5 ln (ms2)	1.85 (0.62–5.46)	0.26	1.17 (0.41–3.29)	0.76
LF/HF	−5	5.17 (2.12–12.62)	<0.001c	2.85 (1.10–7.35)	0.03
Scaling exponent α1	−0.25	1.75 (1.41–2.16)	<0.001c	1.46 (1.16–1.85)	0.001c
Scaling exponent α2	0.25	3.73 (1.86–7.49)	<0.001c	1.25 (0.61–2.53)	0.54
HRT categoryd	0, 1, 2	1.95 (1.22–3.11)	0.005	1.34 (0.81–2.22)	0.26
DC	−1 ms	1.36 (1.15–1.60)	<0.001c	1.13 (0.96–1.34)	0.14

HR, hazard ratio; HRV, heart rate variability; SDNN, SD of normal-to-normal intervals during 24 hours; SDANN, SD of the averages of NN intervals in all 5-minute segments during 24 hours; RMSSD, square root of the mean square of differences between adjacent NN intervals; pNN50, percentage of the number of pairs of adjacent NN R-R intervals differing >50 ms in the total NN intervals; HRVTI, heart rate variability triangular index; ULF, ultra-low frequency (≤0.003 Hz) power; VLF, very-low frequency (0.003–0.04 Hz) power; LF, low frequency (0.04–0.15 Hz) power; HF, high frequency (0.15–0.40 Hz) power; HRT, heart rate turbulence; DC, deceleration capacity.

^aAdjusted for age, left ventricular ejection fraction, serum albumin, C-reactive protein, and calcium × phosphate.

^bHR for 1 unit change in continuous variables or for the presence of features.

^cSignificant after correcting for multiple analyses of 14 variables (P<0.003 for type 1 error level of 0.05).

^dn=68 for survivors and n=37 for nonsurvivors.