TABLE 1.
Baseline and clinical characteristics of AMI admissions stratified by seasons
| Characteristic | Spring (N = 2 826 906) | Summer (N = 2 660 729) | Fall (N = 2 577 885) | Winter (N = 2 815 336) | P |
|---|---|---|---|---|---|
| Type of AMI | <.001 | ||||
| STEMI | 37.1 | 37.4 | 37.1 | 37.1 | |
| NSTEMI | 62.9 | 62.6 | 62.9 | 62.9 | |
| Age (y) | 67.4 ± 14.2 | 67.0 ± 14.3 | 67.5 ± 14.2 | 67.9 ± 14.2 | <.001 |
| Female sex | 39.5 | 39.5 | 40.0 | 39.9 | <.001 |
| Race | <.00 | ||||
| White | 63.1 | 62.8 | 62.4 | 63.1 | |
| Black | 7.9 | 8.0 | 7.9 | 7.8 | 1 |
| Others a | 29.0 | 29.2 | 29.7 | 29.1 | |
| Primary payer | <.001 | ||||
| Medicare | 57.2 | 56.2 | 57.4 | 58.2 | |
| Medicaid | 6.3 | 6.4 | 6.2 | 6.1 | |
| Private | 28.3 | 28.8 | 28.1 | 27.6 | |
| Others b | 8.1 | 8.5 | 8.4 | 8.1 | |
| Quartile of median household income for zip code | <.001 | ||||
| 0‐25th | 24.6 | 24.5 | 24.1 | 24.4 | |
| 26th‐50th | 26.9 | 26.9 | 26.9 | 26.9 | |
| 51st‐75th | 24.2 | 24.3 | 24.3 | 24.3 | |
| 75th‐100th | 24.2 | 24.3 | 24.8 | 24.4 | |
| Charlson Comorbidity Index | <.001 | ||||
| 0–3 | 38.7 | 40.2 | 36.4 | 36.6 | |
| 4–6 | 43.8 | 43.1 | 44.8 | 44.9 | |
| ≥7 | 17.5 | 16.7 | 18.7 | 18.5 | |
| Prior coronary artery bypass grafting | 7.8 | 7.7 | 7.8 | 7.9 | <.001 |
| Hospital teaching status and location | <.001 | ||||
| Rural | 11.6 | 11.5 | 11.6 | 11.6 | |
| Urban nonteaching | 37.4 | 37.3 | 37.9 | 38.2 | |
| Urban teaching | 51.0 | 51.2 | 50.5 | 50.2 | |
| Hospital bed‐size | <.001 | ||||
| Small | 11.9 | 11.6 | 11.5 | 11.8 | |
| Medium | 26.1 | 25.9 | 25.8 | 26.1 | |
| Large | 62.0 | 62.4 | 62.7 | 62.1 | |
| Hospital region | <.001 | ||||
| Northeast | 20.8 | 20.9 | 21.0 | 21.0 | |
| Midwest | 24.6 | 24.7 | 24.5 | 23.9 | |
| South | 36.1 | 36.1 | 35.9 | 36.2 | |
| West | 18.4 | 18.3 | 18.5 | 18.9 | |
| Tertile of admission years | <.001 | ||||
| 2000‐2005 | 34.9 | 34.7 | 36.9 | 36.2 | |
| 2006‐2011 | 30.1 | 29.9 | 31.3 | 30.4 | |
| 2012‐2017 | 35.0 | 35.4 | 31.8 | 33.4 | |
| Weekend admission | 25.8 | 25.9 | 25.8 | 25.7 | <.001 |
| Fibrinolytic therapy (STEMI only) | 4.7 | 4.6 | 4.5 | 4.7 | <.001 |
| Coronary artery bypass grafting | 9.4 | 9.1 | 9.2 | 9.2 | <.001 |
| Cardiac arrest | 4.9 | 5.0 | 5.1 | 5.1 | <.001 |
| Cardiogenic shock | 4.9 | 4.8 | 4.8 | 4.9 | <.001 |
| Multiorgan failure | 9.4 | 9.2 | 9.3 | 9.8 | <.001 |
| Respiratory infections | |||||
| Influenza | 0.1 | 0.0 | 0.0 | 0.4 | <.001 |
| Pneumonia | 6.9 | 5.6 | 6.3 | 8.0 | <.001 |
| Fibrinolysis | 2.2 | 2.2 | 2.1 | 2.2 | <.001 |
| Pulmonary artery catheterization | 1.1 | 1.0 | 1.0 | 1.1 | <.001 |
| Invasive mechanical ventilation | 5.9 | 5.7 | 5.8 | 6.2 | <.001 |
| Acute hemodialysis | 0.5 | 0.5 | 0.6 | 0.6 | <.001 |
Note: Represented as percentage or mean ± SD.
Abbreviations: AMI, acute myocardial infarction; NSTEMI, non‐ST‐segment‐elevation myocardial infarction; STEMI, ST‐segment‐elevation myocardial infarction.
a
Hispanic, Asian or Pacific Islander, Native American, others.
b
Self‐pay, no charge, others.