Relationship Between Index of Cardiac Electrophysiological Balance, Frontal QRS-T Angle and Retinopathy in People with Type 2 Diabetes

Figures & data

Table 1 Comparison of General and Clinical Data of Study Subjects

Variables	NDR	Mild to Moderate NPDR	VTDR	P
N	287	131	247
Sex, % male	193(67.2)	83(63.4)	151(61.1)	0.331
Age, years	57(51–62)	57(49–63)	56(48–62)	0.397
Duration of diabetes, years	6(2–12)^†	10(5–17)^§	13(7–20)*	<0.001
Hypertension, % yes	111(38.7)	57(43.5)^§	138(55.9)*	<0.001
Peripheral neuropathy, % yes	114(39.7)^†	83(63.4)	160(64.8)*	<0.001
Diabetic nephropathy, % yes	13(5.8)^†	35(18.9)^§	65(33.7)*	<0.001
Diabetes treatment, % combine insulin +oral medication	129(45.1)^†	79(60.3)^§	207(83.8)*	<0.001
Current smoker, n %	86(30.0)	38(29.0)	67(27.1)	0.767
HbA1c, %	7.6(6.8–9.1)^†	8.2(7.1–9.9)^§	9.1(7.8–10.5)*	<0.001
Fasting blood glucose, mmol/L	7.52(6.35–9.13)^†	8.06(6.59–10.47)	8.92(6.65–11.60)*	<0.001
TC, mmol/L	4.66(4.12–5.37)	4.62(3.96–5.32)^§	4.97(4.30–6.06)*	<0.001
TG, mmol/L	1.58(1.08–2.37)	1.53(1.20–2.11)^§	1.88(1.32–3.25)*	<0.001
HDL-C, mmol/L	1.13(0.97–1.36)	1.15(0.97–1.29)	1.10(0.93–1.31)	0.321
LDL-C, mmol/L	2.93(2.45–3.40)	2.82(2.40–3.27)	3.01(2.39–3.75)	0.089
SBP, mmHg	131(120–141) †	140(125–154)	140(127–152) *	<0.001
DBP, mmHg	80(73–87)	80(74–89)	80(74–89)	0.632
BMI, kg/m^2	23.94(22.49–25.39) †	25.10(23.14–27.55)	25.26(23.67–27.12) *	<0.001

Notes: Data are expressed as n (%) and median (25 and 75 interquartile). No DR group vs Mild to moderate NPDR group, ^†Represents p<0.05. Mild to moderate NPDR group vs VTDR group, ^§Represents p<0.05. No DR group vs VTDR group, *Represents p<0.05.

Abbreviations: TC, total cholesterol; TG, triglyceride; HDL-C, high-density lipoprotein; LDL-C, low-density lipoprotein; SBP, systolic blood pressure; DBP, diastolic blood pressure; BMI, body mass index.

Table 2 Comparison of Electrocardiographic Indices of Participants

Variables	NDR	Mild to Moderate NPDR	VTDR	P
QT interval, ms	376(360–392)	380(364–396)	374(358–398)	0.297
QTc interval, ms	420(405–435)^†	430(415–445)^§	434(423–452)*	<0.001
Prolonged QTc interval, n %	53(18.5)^†	41(31.3)	98(39.7)*	<0.001
QRS, ms	94(86–100)	94(84–100)	92(84–98)	0.102
iCEB	4.06(3.75–4.33)	4.13(3.77–4.47)	4.10(3.82–4.56)*	0.035
iCEBc	4.50(4.18–4.91)^†	4.64(4.30–5.11)^§	4.76(4.41–5.21)*	<0.001
Frontal QRS-T angle, °	16(9–30)^†	22(9–47)^§	30(15–49)*	<0.001
Widened frontal QRS-T angle, n %	41(14.3)^†	33(25.2)	70(28.3)*	<0.001

Notes: Data are expressed as n (%) and median (25 and 75 interquartile). No DR group vs Mild to moderate NPDR group, ^†Represents p<0.05. Mild to moderate NPDR group vs VTDR group, ^§Represents p<0.05. No DR group vs VTDR group, *Represents p<0.05. Prolonged QTc interval was defined as ≥ 440ms, widened frontal QRS-T angle was defined as ≥73° in men and ≥67° in women.

Abbreviations: QTc interval, corrected QT interval; iCEB, index of cardiac electrophysiological balance; iCEBc, corrected index of cardiac electrophysiological balance.

Table 3 Associations Between DR, iCEBc, Frontal QRS-T Angle and the Other Variables

Variables	DR		iCEBc		Frontal QRS-T Angle
	r	P	r	P	r	P
Age, years	−0.024	0.532	0.114	0.003	0.013	0.728
Duration of diabetes, years	0.325	<0.001	0.144	<0.001	0.035	0.362
Fasting blood glucose, mmol/L	0.177	<0.001	0.066	0.088	0.140	<0.001
HbA1c, %	0.270	<0.001	0.127	0.001	0.108	0.005
BMI, kg/m^2	0.248	<0.001	−0.014	0.291	0.067	0.084
TC, mmol/L	0.083	0.003	0.078	0.045	0.052	0.343
TG, mmol/L	0.099	0.143	0.057	0.143	0.037	0.143
HDL-C, mmol/L	−0.040	0.302	0.105	0.054	−0.005	0.901
LDL-C, mmol/L	0.025	0.516	0.064	0.098	0.034	0.384
SBP, mmHg	0.211	<0.001	0.083	0.033	0.131	0.001
DBP, mmHg	0.037	0.343	0.079	0.052	0.084	0.003
QTc interval, ms	0.301	<0.001
iCEBc	0.205	<0.001
Frontal QRS-T angle, °	0.217	<0.001

Abbreviations: TC, total cholesterol; TG, triglyceride; HDL-C, high-density lipoprotein; LDL-C, low-density lipoprotein; SBP, systolic blood pressure; DBP, diastolic blood pressure; BMI, body mass index; QTc interval, corrected QT interval; iCEBc, corrected index of cardiac electrophysiological balance.

Table 4 Logistic Regression Analysis of Frontal QRS-T Angle and iCEBc with DR Risk

Model	OR	95%Cl	P
iCEBc
Model 1	2.284	1.696 –3.077	<0.001
Model 2	2.135	1.447–3.150	<0.001
Model 3	2.217	1.464–3.358	<0.001
Model 4
Male	2.090	1.244–3.512	0.005
Female	3.227	1.436 –7.253	0.005
Frontal QRS-T angle
Model 1	1.020	1.013–1.027	<0.001
Model 2	1.020	1.011–1.028	<0.001
Model 3	1.017	1.008 –1.025	<0.001
Model 4
Male	1.013	1.003 –1.023	0.011
Female	1.028	1.009–1.048	0.004

Notes: iCEBc, corrected index of cardiac electrophysiological balance; model 1: Crude model; model 2: adjusted for age, sex, diabetes duration, hypertension, current smoker, peripheral neuropathy, diabetic nephropathy and use of combined diabetes treatment; model 3: additionally adjusted for SBP, DBP, BMI, HbA1c, FPG, TC, TG, HDL and LDL at the base of model 2. Model 4 is stratified according to gender.

Table 5 Correlation Analysis of Quartiles of iCEBc and Frontal QRS-T Angle with DR Risk

Variables	Prevalence of DR (%)	Univariate			Multivariate
		OR	95% Cl	P	OR	95% Cl	P
iCEBc
Q1, ≤4.28	72(19.0)	Reference		<0.001	Reference		0.016
Q2, 4.29–4.63	90(23.8)	1.526	0.990 –2.351	0.055	1.248	0.725–2.149	0.424
Q3, 4.64–5.05	100(26.5)	1.978	1.278–3.062	0.002	1.743	0.996 –3.053	0.052
Q4,≥5.06	116(30.7)	3.029	1.928–4.759	<0.001	2.612	1.411–4.834	0.002
Frontal QRS-T angle, °
Q1, ≤10	85(22.5)	Reference		<0.001	Reference		0.002
Q2, 11–23	75(19.8)	1.106	0.720–1.698	0.646	1.067	0.627–1.814	0.811
Q3, 24–40	103(27.2)	1.967	1.280 –3.021	0.002	1.998	1.167–3.422	0.012
Q4,≥41	115(30.4)	2.790	1.789–4.352	<0.001	2.430	1.420 –4.160	0.001

Note: iCEBc, corrected index of cardiac electrophysiological balance.

Figure 1 Relationship between iCEBc quartiles and the prevalence of DR.

Figure 2 Relationship between frontal QRS-T angle quartiles and the prevalence of DR.