Table I.
Characteristics of Patients Hospitalized With Acute Myocardial Infarction (AMI) According to Whether They Were Transported to Central Massachusetts Medical Centers By Emergency Medical Services (EMS)
| Total Population | Patients With ST-Segment Elevation AMI | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Characteristics | EMS (+) (n=3,789) | EMS (-) (n=1,505) | P value | EMS (+) (n=1,325) | EMS (-) (n=545) | P value | ||||
| Age (mean, years) | 3,706 | 73.8 | 1,497 | 65.9 | <.001 | 1,305 | 69.7 | 542 | 62.5 | <.001 |
| Age (years) | n | % | n | % | n | % | n | % | ||
| <55 | 374 | 9.9 | 363 | 24.1 | <.001 | 230 | 17.4 | 171 | 31.4 | |
| 55-64 | 526 | 13.9 | 311 | 20.7 | 241 | 18.2 | 128 | 23.5 | <.001 | |
| 65-74 | 767 | 20.3 | 351 | 23.3 | 280 | 21.2 | 125 | 22.9 | ||
| 75-84 | 1,218 | 32.2 | 338 | 22.5 | 354 | 26.7 | 88 | 16.2 | ||
| ≥85 | 901 | 23.8 | 142 | 9.4 | 219 | 16.5 | 33 | 6.1 | ||
| Male | 1,922 | 50.7 | 996 | 66.2 | <.001 | 728 | 54.9 | 390 | 71.6 | <.001 |
| White | 3,387 | 89.4 | 1,352 | 89.8 | 0.63 | 1,177 | 88.8 | 490 | 89.9 | 0.50 |
| Prior DNR order | 330 | 8.7 | 35 | 2.3 | <.001 | 70 | 5.3 | 9 | 1.7 | <.001 |
| Medical History | ||||||||||
| Angina | 776 | 20.5 | 282 | 18.7 | 0.15 | 228 | 17.2 | 74 | 13.6 | <.05 |
| Hypertension | 2,725 | 71.9 | 976 | 64.9 | <.001 | 858 | 64.8 | 308 | 56.5 | <.001 |
| Diabetes | 1,321 | 34.9 | 457 | 30.4 | <.005 | 356 | 26.9 | 134 | 24.6 | 0.31 |
| Heart failure | 1,148 | 30.3 | 215 | 14.3 | <.001 | 224 | 16.9 | 43 | 7.9 | <.001 |
| Stroke | 529 | 14.0 | 124 | 8.2 | <001 | 147 | 11.1 | 30 | 5.5 | <.001 |
| Cancer | 606 | 16.0 | 202 | 13.4 | <.05 | 183 | 13.8 | 70 | 12.8 | 0.58 |
| Kidney disease | 733 | 19.4 | 178 | 11.8 | <.001 | 175 | 13.2 | 39 | 7.2 | <.001 |
| Symptoms | ||||||||||
| Chest pain | 2,533 | 66.9 | 1,205 | 80.1 | <.001 | 1,014 | 76.5 | 478 | 87.1 | <.001 |
| Shortness of breath | 2,256 | 59.5 | 801 | 53.2 | <.001 | 728 | 54.9 | 277 | 50.8 | 0.10 |
| Abdominal pain | 292 | 7.7 | 120 | 8.0 | 0.79 | 82 | 6.2 | 40 | 7.3 | 0.36 |
| Arm/shoulder pain | 460 | 12.2 | 302 | 20.1 | <.001 | 202 | 15.3 | 148 | 27.2 | <.001 |
| Left arm pain | 770 | 20.3 | 453 | 30.1 | <.001 | 371 | 28.0 | 209 | 38.4 | <.001 |
| Back pain | 432 | 11.4 | 222 | 14.8 | <.001 | 185 | 14.0 | 85 | 15.6 | 0.37 |
| Rapid heart rate/palpitations | 274 | 7.2 | 101 | 6.7 | 0.55 | 61 | 4.6 | 28 | 5.1 | 0.62 |
| Diaphoresis | 1,360 | 35.9 | 520 | 34.6 | 0.39 | 631 | 47.6 | 254 | 46.6 | 0.69 |
| AMI Characteristics | ||||||||||
| Initial | 2,332 | 61.6 | 1,043 | 69.3 | <.001 | 924 | 69.7 | 427 | 78.4 | <.001 |
| Q Wave | 854 | 22.8 | 357 | 24.0 | 0.35 | 633 | 48.0 | 265 | 48.9 | 0.71 |
| STEMI | 1,325 | 35.0 | 545 | 36.2 | 0.39 | |||||
| Weekend | 1,072 | 28.4 | 465 | 31.2 | <.05 | 390 | 29.6 | 181 | 33.6 | 0.09 |
| Time of Day | ||||||||||
| 12:00 a.m.-5:59 a.m. | 656 | 17.4 | 195 | 13.0 | 223 | 16.9 | 80 | 14.8 | ||
| 6:00 a.m.-11:59 a.m. | 1,190 | 31.5 | 475 | 31.7 | <.01 | 419 | 31.7 | 148 | 27.4 | 0.07 |
| 12:00 p.m.-5:59 p.m. | 1,116 | 29.5 | 508 | 33.9 | 408 | 30.9 | 197 | 36.4 | ||
| 6:00 p.m.-11:59 p.m. | 819 | 21.7 | 320 | 21.4 | 272 | 20.6 | 116 | 21.4 | ||
| Physiologic findings (at hospital admission) | ||||||||||
| Systolic blood pressure (mean, mmHg) | 3,599 | 138.4 | 1,423 | 151.7 | <.001 | 1,242 | 134.6 | 513 | 152.0 | <.001 |
| Diastolic blood pressure (mean, mmHg) | 3,450 | 74.3 | 1,415 | 83.6 | <.01 | 1,194 | 75.7 | 507 | 86.3 | <.001 |
| Laboratory findings (at hospital admission) | ||||||||||
| Serum glucose (mean, mg/dl) | 3,711 | 186.7 | 1,476 | 165.2 | <.001 | 1,291 | 181.7 | 534 | 168.6 | <0.01 |
| Total cholesterol (mean, mg/dl) | 1,721 | 175.2 | 833 | 181.2 | 0.57 | 692 | 176.6 | 325 | 187.6 | <.001 |
| Estimated GFR* (mean) | 3,654 | 56.1 | 1,476 | 65.7 | 0.28 | 1,285 | 62.3 | 532 | 72.0 | <.001 |
*
glomerular filtration rate (ml/min/1.73m2)