Table 3.
Subject Characteristics Stratified by Enrollment Phase (N=437)
| Characteristic* | Phase 1 (n=107) | Phase 2 (n=104) | P-value for Phases 1 vs. 2† | Phase 3 (n=226) |
|---|---|---|---|---|
| Age (years) | 60.9 ± 15.5 | 62.1 ± 13.5 | 0.54 | 63.5 ± 13.6 |
| Male gender | 56.1% (60) | 81.7% (85) | <0.0001 | 71.2% (161) |
| Hispanic ethnicity | 3.7% (4) | 4.8% (5) | 0.70 | 17.0% (38) |
| Race | 0.53 | |||
| White | 72.0% (77) | 68.3% (71) | 77.4% (175) | |
| Black | 20.6% (22) | 22.1% (23) | 8.4% (19) | |
| Other | 3.7% (4) | 1.9% (2) | 4.4% (10) | |
| Unknown | 3.7% (4) | 7.7% (8) | 9.7% (22) | |
| Medical History | ||||
| Myocardial infarction | 23.4% (25) | 35.6% (37) | 0.06 | 35.8% (81) |
| Coronary artery bypass graft | 15.9% (17) | 15.4% (16) | 0.92 | 17.3% (39) |
| Congestive heart failure | 13.1% (14) | 26.0% (27) | 0.02 | 15.0% (34) |
| Percutaneous coronary intervention (PCI) | 21.5% (23) | 24.0% (25) | 0.66 | 34.1% (77) |
| Angina | 21.5% (23) | 14.4% (15) | 0.18 | 8.8% (20) |
| Arrhythmia | 24.3% (26) | 22.1% (23) | 0.71 | 18.1% (41) |
| Diabetes | 29.0% (31) | 28.8% (30) | 0.99 | 26.5% (60) |
| Hypertension | 62.6% (67) | 63.5% (66) | 0.90 | 68.6% (155) |
| Hypercholesterolemia | 48.6% (52) | 37.5% (39) | 0.11 | 51.8% (117) |
| Stroke | 6.5% (7) | 8.7% (9) | 0.57 | 8.4% (19) |
| EMS Data | ||||
| Primary symptom chest pain | 77.6% (83) | 85.6% (89) | 0.14 | 88.5% (200) |
| Systolic blood pressure (mmHg) | 145.2 ± 31.3 | 147.7± 35.2 | 0.59 | 142.2 ± 33.8 |
| Heart rate (bpm) | 91.6 ± 24.9 | 86.1 ± 23.4 | 0.11 | 85.6 ± 25.3 |
| ACI-TIPI (% prediction of ACS) | 48.0 ± 26.2 | 70.5 ± 22.7 | <0.0001 | 79.4 ± 17.3 |
| TPI trigger | 17.0% (18) | 47.1% (49) | <0.0001 | 37.2% (84) |
| ACI-TIPI ≥ 75% or TPI triggered | 27.6% (29) | 72.5% (74) | <0.0001 | 81.2% (181) |
Data are presented as means ± standard deviations (age, blood pressure, heart rate, ACI-TIPI score) or percent (sample size) for all other characteristics. There were missing data for some characteristics. Specifically, ethnicity data were missing for two subjects (Phase 3). Systolic blood pressure, heart rate and the ACI-TIPI score data were missing for less than 3% of subjects. Data needed to determine if either TIPI ≥ 75 or TPI trigger was true were missing for seven subjects (two in Phase 1, two in Phase 2, and three in Phase 3).
P-values are from chi-square test (gender, ethnicity, site), Fisher’s exact test (race), or t-test (age) used to compare characteristics between Phase 1 and Phase 2.