Table 4. HRV feature correlations with DM years for the 8 T2DM groups.

HRV Features	CONT	ALL-C	RNp	NNp	RN	DPNn	R	Np
mRR	0.07	0.41	0.45*	0.2	-0.08	0.04	0.15	0.1
SDNN	-0.32	-0.19	0.18	0.2	-0.01	-0.27	-0.11	-0.04
SD1	-0.25	0.19	0.1	-0.4	-0.2	-0.16	-0.33	0.17
SD2	-0.32	-0.29	0.18	0.2	-0.003	-0.25	-0.1	-0.08
LF	-0.15	-0.06	0.3	0.2	-0.02	-0.28	-0.15	0.22
HF	-0.21	0.39	0.23	0.2	-0.12	-0.1	-0.29	-0.03
LF/HF	-0.01	-0.39	-0.26	0.6	-0.06	-0.39	0.11	-0.02
E1	-0.29	0.27	0.13	-0.4	-0.15	-0.13	0.3	0.09
E2	-0.24	0.17	0.06	-0.4	-0.18	-0.28	-0.41*	0.15
E3	-0.23	-0.09	-0.06	-0.4	-0.12	-0.34	-0.42*	0.17
E4	-0.24	-0.06	0.01	-0.4	-0.23	-0.62*	-0.24	0.13
E5	-0.21	-0.06	0.03	0.2	-0.12	-0.41	-0.35*	0.11
E6	-0.23	-0.1	-0.09	0.2	-0.06	-0.38	-0.43*	0.13
E7	-0.22	-0.16	-0.03	0.2	-0.14	-0.45	-0.39*	0.07
E8	-0.24	-0.1	-0.05	0.2	-0.12	-0.41	-0.29	0.12

*: significantly different from CONT (p<0.05).