Table 1. Clinical covariates.
| Covariate | Overall (n = 154) | Train | Validation | Train + Validation | Test | p value |
|---|---|---|---|---|---|---|
| (n = 76) | (n = 32) | (n = 108) | (n = 46) | |||
| Age, y | 48.0(38.0–58.0) | 45.0(37.0–57.5) | 49.0(41.0–60.2) | 48.0(38.0–59.0) | 49.0(36.0–57.0) | 0.591 |
| Male, n (%) | 108(70) | 52(68) | 22(69) | 34(31) | 34(74) | 0.789 |
| Height, m | 1.7(1.7–1.8) | 1.7(1.6–1.8) | 1.7(1.7–1.8) | 1.7(1.7–1.8) | 1.7(1.7–1.8) | 0.480 |
| Weight, kg | 79(67.0–88.0) | 83.0(61.0–88.5) | 78.0(70.7–86.2) | 79.0(65.0–87.0) | 80.0(72.0–94.0) | 0.504 |
| Dyslipidaemia, n (%) | 35(26) | 19(29) | 4(14) | 23(24) | 12(29) | 0.243 |
| Arterial hypertension, n (%) | 52(38) | 22(34) | 13(45) | 35(37) | 17(41) | 0.539 |
| Smoker | 0.066 | |||||
| Current smoker, n (%) | 31(23) | 17(26) | 7(24) | 24(25) | 7(17) | |
| Ex-smoker | 17(13) | 13(20) | 1(3) | 14(15) | 3(7) | |
| Diabetes mellitus, n (%) | 18(13) | 4(6) | 4(14) | 8(8) | 10(24) | 0.027 |
| Familial history | ||||||
| CAD, n (%) | 18(13) | 7(10) | 4(14) | 11(11) | 7(17) | 0.578 |
| Cardiomyopathy, n (%) | 22(16) | 16(24) | - | 16(17) | 6(15) | 0.013 |
| SCD, n (%) | 7(5) | 5(7) | - | 5(5) | 2(5) | 0.318 |
| COPD, n (%) | 3(2) | 2(3) | - | 2(2) | 1(2) | 0.646 |
| Creatinine, mmol/l | 81.0(69.0–91.2) | 82.0(66.5–91.5) | 84.0(67.7–101.2) | 82.0(69.0–93.0) | 79.0(71.0–89.0) | 0.406 |
| NYHA | 0.826 | |||||
| I, n (%) | 85(56) | 41(55) | 16(50) | 57(53) | 28(61) | |
| II, n (%) | 14(9) | 6(8) | 4(12) | 10(9) | 4(9) | |
| III, n (%) | 50(33) | 27(36) | 11(34) | 38(35) | 12(26) | |
| IV, n (%) | 4(3) | 1(1) | 1(3) | 2(2) | 2(4) | |
| NT-proBNP, pg/l | 923(593–2309) | 845(610–2442) | 880(309–1786) | 845(466–1949) | 1009(646–2523) | 0.947 |
| Sinus rhythm, n (%) | 113(86) | 58(88) | 21(78) | 79(85) | 34(87) | 0.428 |
| Atrial fibrillation, n (%) | 20(15) | 8(12) | 7(13) | 15(16) | 5(13) | 0.215 |
| LBBB, n (%) | 56(36) | 36(47) | 9(28) | 45(42) | 11(24) | 0.018 |
CAD: coronary artery disease; COPD: chronic obstructive pulmonary disease; LBBB: left bundle branch block; NYHA: New York Heart Association; SCD: sudden cardiac death. Data are reported as median (1st– 3rd quartile) for continuous variables and as total number (%) for categorical variables. Differences between “train”, “validation” and “test” groups were assessed using the Mann‒Whitney test for continuous variables and the Pearson chi square test of Fisher exact test for categorical variables. P values < 0.05 were considered statistically significant.