Independent Influence of Blood Pressure on QTc Interval: Results from a General Chinese Population

Table 1

Characteristics of the study population.

Variable	Normal QTc	Prolonged QTc	P value
	(n = 9,182)	(n = 1,371)
Age, years	53.2 ± 10.3	56.8 ± 10.8	< 0.001
Male	4,239 (46.2)	536 (39.1)	< 0.001
Race of Han	8,708 (94.8)	1,303 (95.0)	0.751
BMI, kg/m^2	24.7 ± 3.6	25.3 ± 3.9	< 0.001
SBP, mmHg	139.9 ± 22.5	152.6 ± 25.5	< 0.001
DBP, mmHg	81.3 ± 11.3	86.5 ± 13.0	< 0.001
Hypertension	4,359 (47.5)	982 (71.6)	< 0.001
FBG, mmol/L	5.84 ± 1.50	6.31 ± 2.27	< 0.001
TC, mmol/L	5.21 ± 1.07	5.40 ± 1.16	< 0.001
TG, mmol/L	1.59 ± 1.39	1.97 ± 1.96	< 0.001
LDL-C, mmol/L	2.90 ± 0.81	3.05 ± 0.85	< 0.001
HDL-C, mmol/L	1.41 ± 0.38	1.40 ± 0.40	0.441
SUA, mg/dL	4.87 ± 1.40	4.99 ± 1.53	0.007
Calcium, mmol/L	2.32 ± 0.13	2.34 ± 0.12	< 0.001
Potassium, mmol/L	4.21 ± 0.34	4.09 ± 0.38	< 0.001
Magnesium, mmol/L	0.85 ± 0.11	0.85 ± 0.08	0.117
Current smoker	3,243 (35.3)	474 (34.6)	0.590
Current drinker	2,073 (22.6)	264 (19.3)	0.006
LVIDd, cm	4.70 ± 0.41	4.74 ± 0.45	0.001
IVS, cm	0.87 ± 0.12	0.91 ± 0.14	< 0.001
PWT, cm	0.85 ± 0.10	0.88 ± 0.12	< 0.001
LVMI, g/m^2	81.1 ± 18.0	86.5 ± 21.7	< 0.001
LVH	837 (9.1)	251 (18.3)	< 0.001
Heart rate, bpm	70.3 ± 11.6	79.9 ± 13.1	< 0.001
QTc interval, ms	423.3 ± 19.2	469.5 ± 18.9	< 0.001
History of heart disease†	830 (9.0)	210 (15.3)	< 0.001
Medication used‡	4,745 (51.7)	870 (63.5)	< 0.001

Abbreviations. BMI: body mass index; DBP: diastolic blood pressure; FBG: fasting blood glucose; HDL-C: high density lipid cholesterol; IVS: interventricular septum; LDL-C: low density lipid cholesterol; LVH: left ventricular hypertrophy; LVIDd: left ventricular internal diameter at end-diastole; LVMI: left ventricular mass index; PWT: posterior wall thickness; QTc: QT interval corrected for heart rate with Bazett’s formula; SBP: systolic blood pressure; TC: total cholesterol; TG: triglycerides.
Note. Data are presented as mean ± standard deviation or n (%).
†Including coronary heart disease, arrhythmia, and heart failure.
‡Indicating any self-reported medication used in the past 2 weeks.