Table 1.
Baseline characteristics of the study population
| All* | Before propensity score matching | After propensity score matching | |||
| QTc | Prolonged QTc | QTc | Prolonged QTc | ||
| <440 ms (men and women) | ≥450 ms (men) ≥460 ms (women) |
<440 ms (men and women) | ≥450 ms (men) ≥460 ms (women) |
||
| N | 3869 | 3296 | 253 | 496 | 248 |
| Sex | |||||
| Male (%) | 1859 (48.0) | 1634 (49.6) | 121 (47.8) | 229 (46.2) | 119 (48.0) |
| Age (median, IQR) | 38 (25–53) | 36 (24–51) | 52 (36–68) | 53 (37–69) | 51 (35–66) |
| 18–50, n (%) | 2747 (71.0) | 2444 (74.2) | 119 (47.0) | 236 (48.0) | 119 (48.0) |
| 51–69, n (%) | 788 (20.4) | 611 (18.5) | 77 (30.4) | 140 (28.5) | 77 (31.0) |
| ≥70, n (%) | 334 (8.6) | 241 (7.3) | 57 (22.5) | 116 (23.6) | 52 (21.0) |
| Charlson Comorbidity Index, n (%) | |||||
| CCI=0 | 2747 (71.0) | 2395 (72.7) | 140 (55.3) | 263 (53.0) | 140 (56.5) |
| CCI=1 | 718 (18.6) | 587 (17.8) | 60 (23.7) | 133 (26.8) | 58 (23.4) |
| CCI≥2 | 404 (10.4) | 314 (9.5) | 53 (20.9) | 100 (20.2) | 50 (20.2) |
| Myocardial infarction or congestive heart failure, n (%) | 185 (4.8) | 136 (4.1) | 32 (12.6) | 55 (11.1) | 29 (11.7) |
| QT-prolonging drugs, n (%) | 1518 (39.2) | 1248 (37.9) | 110 (43.5) | 213 (42.9) | 109 (44.0) |
| ECG measurements | |||||
| Heart rate (median, IQR) | 85 (73–99) | 87 (74–101) | 76 (65–84) | 76 (65–87) | 76 (65–85) |
| QTc ≥500 ms, n (%) | 27 (0.7) | – | 27 (10.7) | – | 27 (10.9) |
| Any diagnose of poisoning, n (%) | 2676 (69.2) | 2282 (69.2) | 153 (60.5) | 310 (62.5) | 151 (60.9) |
| Group of poisoning, n (%) | |||||
| 1. Analgesics and drugs of abuse | 397 (14.8) | 333 (14.6) | 21 (13.7) | 41 (13.2) | 21 (13.9) |
| 2. Psychotropic drugs and drugs affecting the central nervous system | 805 (30.1) | 695 (30.5) | 49 (32.0) | 103 (33.2) | 49 (32.5) |
| 3. Organic and chemical substances, non-medical | 502 (18.8) | 437 (19.1) | 24 (15.7) | 50 (16.1) | 24 (15.9) |
| 4. Others | 470 (17.6) | 392 (17.2) | 30 (19.6) | 54 (17.4) | 29 (19.2) |
| 5. Multidrug | 502 (18.8) | 425 (18.6) | 29 (19.0) | 62 (20.0) | 28 (18.5) |
| Clinics, n (%) | |||||
| The University Hospital Skåne, Lund | 1794 (46.4) | 1539 (46.7) | 125 (49.4) | 247 (49.8) | 124 (50.0) |
| Odense University Hospital | 501 (12.9) | 419 (12.7) | 28 (11.1) | 50 (10.1) | 28 (11.3) |
| Helsingborg Hospital | 1372 (35.5) | 1176 (35.7) | 81 (32.0) | 170 (34.3) | 79 (31.9) |
| Hospital of South West Jutland | 202 (5.2) | 162 (4.9) | 19 (7.5) | 29 (5.8) | 17 (6.9) |
*In the total cohort patients with a near-overlapping QTc interval (440–449 ms men, 440–459 ms women) are included (n=320).
CCI, Charlson Comorbidity Index.