Table 2.
Clinical characteristics of the training and the internal and external validation cohorts
| Training cohort | Internal validation cohort | External validation cohort | |
|---|---|---|---|
| n = 1510 | n = 158 | n = 1367 | |
| Age, years | 67 (60–74) | 68 (61–74) | 71 (63–77)*,** |
| Male | 1141 (76) | 127 (80) | 1058 (77) |
| Height, cm | 172 (165–176) | 172 (167–176) | 170 (165–177) |
| Weight, kg | 80 (70–91) | 80 (72–92) | 78 (69–90)*,** |
| BMI, kg/m2 | 27 (24–31) | 27 (24–30) | 26 (24–30)* |
| SBP, mmHg | 121 (110–134) | 118 (110–134) | 120 (110–135) |
| NYHA functional class | |||
| I | 7 (1) | 1 (1) | 21 (2) |
| II | 393 (33) | 27 (17) | 280 (20) |
| III | 523 (44) | 115 (73) | 937 (69) |
| IV | 274 (23) | 15 (9) | 129 (9) |
| Ischemic HF aetiology | 767 (51) | 95 (60) | 714 (55)* |
| LVEF, % | 28 (23–33) | 28 (24–33) | 25 (20–30)*,** |
| CRT-D | 688 (46) | 32 (20) | 1026 (75)*,** |
| Hypertension | 1055 (70) | 97 (61) | 319 (24)*,** |
| Diabetes | 560 (37) | 64 (41) | 404 (30)*,** |
| Atrial fibrillation | 584 (39) | 48 (30) | 337 (25)* |
| QRS duration, ms | 160 (141–180) | 160 (150–180) | 160 (134–180)*,** |
| LBBB | 1054 (70) | 128 (81) | 997 (73)** |
| Haemoglobin, g/dL | 13.6 (12.3–14.8) | 14.0 (13.0–15.0) | 13.1 (11.8–14.3)*,** |
| Serum sodium, mmol/L | 138 (136–141) | 138 (136–140) | 139 (137–141)*,** |
| Creatinine, µmol/L | 103 (84–133) | 110 (80–136) | 106 (85–136) |
| GFR, mL/min/1.73m2 | 59 (43–74) | 62 (46–85) | 56 (42–74)** |
| NT-proBNP, pg/mL | 1950 (841–4468) | 2608 (1377–5087) | 2113 (876–4455) |
| ACE-I/ARB | 1197 (91) | 146 (95) | 1187 (87)*,** |
| Beta-blockers | 1165 (88) | 143 (91) | 1144 (84)*,** |
| Diuretics | 1144 (76) | 129 (82) | 1187 (87)* |
| MRA | 845 (64) | 110 (70) | 636 (47)*,** |
| Statin | 772 (59) | 97 (61) | 761 (56) |
| Antiarrhythmic medication | 394 (30) | 47 (30) | 363 (27) |
| 1-year all-cause mortality | 230 (15) | 39 (25) | 122 (9) |
Continuous variables are presented as mean ± standard deviation or median (interquartile range), whereas categorical variables are reported as frequencies (percentages). The characteristics of the external validation cohort were compared with those of the training and internal validation cohorts using unpaired Student’s t-test or Mann–Whitney U test for continuous variables and Chi-squared or Fisher’s exact test for categorical variables, as appropriate.
Abbreviations as in Table 1.
* P < 0.05 vs. the training cohort.
** P < 0.05 vs. the internal validation cohort.