Subgroup analysis depending on the type of ACS
| ACS group | IHM | N | NRR | P values | AUC | 2YM | N | NRR | P values | AUC |
| STEMI | No | 131 | 15.5±1.8 | 0.018 | 0.847 | No | 120 | 15.4±1.6 | 0.006 | 0.717 |
| Yes | 4 (3.0%) | 17.6±1.3 | Yes | 15 (12.5%) | 16.9±12.5 | |||||
| NSTEMI | No | 424 | 15.9±2.1 | <0.001 | 0.747 | No | 367 | 15.8±2.0 | <0.001 | 0.675 |
| Yes | 16 (3.7%) | 17.9±2.1 | Yes | 73 (19.9%) | 17.2±2.4 | |||||
| UAP | No | 284 | 15.0±1.8 | 0.007 | 1.000 | No | 265 | 15.0±1.8 | 0.266 | 0.575 |
| Yes | 1 (0.3%) | 20.6 | Yes | 20 (7.5%) | 15.6±2.4 |
AUC, area IHM, intrahospital mortality; NRR, nocturnal respiration rate; NSTEMI, non-ST-elevation myocardial infarction; STEMI, ST-elevation myocardial infarction; UAP, unstable angina pectoris; 2YM, 2-year mortality.