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/m2 | 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/m2 | 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.