Table 3. . Clinical characteristics compared between patients without and with prolonged QTc in the unmatched and propensity-matched samples.
| Characteristics | Unmatched sample | p-value | Propensity-matched sample | p-value | ||
|---|---|---|---|---|---|---|
| Without prolonged QTc | With prolonged QTc | Without prolonged QTc | With prolonged QTc | |||
| Patients, n (%) | 5,350 (88.0) | 733 (12.0) | __ | 733 (50.0) | 733 (50.0) | __ |
| Aged 68 years or older, n (%) | 2,967 (55.5) | 403 (55.0) | 0.838 | 297 (40.5) | 263 (35.9) | 0.076 |
| Female, n (%) | 2,985 (55.8) | 385 (52.5) | 0.103 | 373 (50.9) | 385 (52.5) | 0.565 |
| Hypokalemia, n (%) | 325 (6.1) | 103 (14.1) | <0.001 | 86 (11.7) | 103 (14.1) | 0.212 |
| Hypocalcemia, n (%) | 1,005 (18.8) | 298 (40.7) | <0.001 | 317 (43.2) | 298 (40.7) | 0.341 |
| Hypomagnesemia, n (%) | 1,059 (19.8) | 128 (17.5) | 0.149 | 155 (21.1) | 128 (17.5) | 0.085 |
| BMI (kg/m2), mean (SD) | 30.3 (7.5) | 29.9 (7.9) | 0.343 | 30.7 (7.5) | 29.9 (7.9) | 0.070 |
| CHF, n (%) | 369 (6.9) | 148 (20.2) | <0.001 | 137 (18.7) | 148 (20.2) | 0.509 |
| HTN, n (%) | 3,010 (56.3) | 495 (67.5) | <0.001 | 509 (69.4) | 495 (67.5) | 0.465 |
| CAD, n (%) | 2,279 (42.6) | 387 (52.8) | <0.001 | 393 (53.6) | 387 (52.8) | 0.794 |
| Hypothyroidism, n (%) | 754 (14.1) | 105 (14.3) | 0.911 | 119 (16.2) | 105 (14.3) | 0.345 |
| History of MI, n (%) | 374 (7.0) | 96 (13.1) | <0.001 | 91 (12.4) | 96 (13.1) | 0.754 |
| DM, n (%) | 1,097 (20.5) | 222 (30.3) | <0.001 | 234 (31.9) | 222 (30.3) | 0.535 |
| DM complicated, n (%) | 353 (6.6) | 87 (11.9) | <0.001 | 91 (12.4) | 87 (11.9) | 0.810 |
| History of Stroke, n (%) | 529 (9.9) | 121 (16.5) | <0.001 | 121 (16.5) | 121 (16.5) | 1.000 |
| CKD, n (%) | 707 (13.2) | 184 (25.1) | <0.001 | 202 (27.6) | 184 (25.1) | 0.313 |
| Severe liver disease, n (%) | 82 (1.5) | 30 (4.1) | <0.001 | 35 (4.8) | 30 (4.1) | 0.612 |
| Liver disease, n (%) | 598 (11.2) | 115 (15.7) | 0.001 | 134 (18.3) | 115 (15.7) | 0.211 |
| COPD, n (%) | 429 (8.0) | 96 (13.1) | <0.001 | 97 (13.2) | 96 (13.1) | 1.000 |
| Cancer, n (%) | 385 (7.2) | 51 (7.0) | 0.887 | 53 (7.3) | 51 (7.0) | 0.925 |
| PVD, n (%) | 458 (8.6) | 113 (15.4) | <0.001 | 118 (16.1) | 113 (15.4) | 0.774 |
| Arrhythmia, n (%) | 974 (18.2) | 223 (30.4) | <0.001 | 209 (28.5) | 223 (30.4) | 0.456 |
| History of alcohol consumption, n (%) | 189 (3.5) | 47 (6.4) | <0.001 | 44 (6.0) | 47 (6.4) | 0.829 |
| Loop diuretic, n (%) | 659 (12.3) | 261 (35.6) | <0.001 | 254 (34.7) | 261 (35.6) | 0.743 |
| Digoxin, n (%) | 21 (0.4) | 16 (2.2) | <0.001 | 15 (2.0) | 16 (2.2) | 1.000 |
| Beta-blockers, n (%) | 1,453 (27.2) | 341 (46.5) | <0.001 | 350 (47.7) | 341 (46.5) | 0.676 |
| >2 QT-prolonging drugs, n (%) | 2,771 (51.8) | 272 (37.1) | <0.001 | 274 (37.4) | 272 (37.1) | 0.957 |
| Elixhauser score (IQR) | 7.0 (13.0) | 11.0 (14.0) | <0.001 | 12 (14.0) | 11 (14.0) | 0.547 |
| Charlson score (IQR) | 3 (5.0) | 4 (5.0) | <0.001 | 5 (5) | 4 (5) | 0.727 |
| Days between start date of QT-prolonging drug and maximum QTc value (IQR) | 1622 (1395) | 1607 (1457) | 0.964 | 1739 (1368) | 1607 (1457) | 0.108 |
Bolded p-values <0.05.
BMI: Body mass index; CAD: Coronary artery disease; CHF: Congestive heart failure; CKD: Chronic kidney disease; COPD: Chronic obstructive pulmonary disease; CrCl: Creatinine clearance; DM: Diabetes mellitus; HTN: Hypertension; IQR: Interquartile range; MI: Myocardial infarction; PVD: Peripheral vascular disease.