Table 2. Multivariable Cox Proportional Hazards Regression Model Analysis for Risk of Cardiac Events: First Cardiac Events (Syncope, VF, or Aborted Cardiac Arrest).
| Characteristic | Males | Females | ||
|---|---|---|---|---|
| HR (95% CI) | P Value | HR (95% CI) | P Value | |
| LQT1 | ||||
| Probands per family | 1.44 (0.83-2.43) | .17 | 1.92 (1.28-2.88) | .002 |
| Year of birth per 1-y increase | 1.02 (1.00-1.03) | .03 | 1.01 (1.00-1.03) | .01 |
| QTc per 10-ms increase | 1.07 (1.02-1.12) | .006 | 1.06 (1.02-1.10) | .003 |
| Pathogenic variant location | ||||
| S5-pore-S6 vs N/C-term | 1.28 (0.75-2.17) | .36 | 1.88 (1.02-2.93) | .006 |
| Nonpore MS vs N/C-term | 1.50 (0.87-2.58) | .15 | 1.37 (0.81-2.33) | .25 |
| S5-pore-S6 vs nonpore MS | 0.85 (0.49-1.47) | .15 | 1.37 (0.86-2.18) | .19 |
| LQT2 | ||||
| Probands per family | 3.62 (1.82-7.20) | <.001 | 3.14 (1.97-5.00) | <.001 |
| Year of birth per 1-y increase | 1.03 (1.01-1.05) | <.001 | 1.06 (1.05-1.08) | <.001 |
| QTc per 10-ms increase | 1.09 (1.03-1.15) | .002 | 1.03 (0.99-1.06) | .11 |
| Pathogenic variant location | ||||
| S5-pore-S6 vs N/C-term | 1.99 (1.11-3.57) | .02 | 1.64 (1.18-2.27) | .003 |
| Nonpore MS vs N/C-term | 1.54 (0.71-3.38) | .28 | 0.94 (0.54-1.63) | .82 |
| S5-pore-S6 vs nonpore MS | 1.29 (0.59-2.82) | .53 | 1.75 (0.99-3.09) | .05 |
Abbreviations: HR, hazard ratio; LQT1, long QT syndrome type 1; LQT2, long QT syndrome type 2; MS, membrane spanning; N/C-term, N-terminus or C-terminus variant; S5-pore-S6, variants of pore site and segment 5 (S5) to segment 6 (S6); VF, ventricular fibrillation.