Table 2. Clinical and Safety Outcomes by Treatment Groupa.
| Variable | Unadjusted Analysis | P Value | Adjusted (IPTW) Analysisb | P Value | ||
|---|---|---|---|---|---|---|
| Clinical Evaluation Only (n = 118) |
Clinical Evaluation and Noninvasive Testing (n = 882) |
Clinical Evaluation Only (n = 118) |
Clinical Evaluation and Noninvasive Testing (n = 882) |
|||
| Clinical Outcomes, No. (%) | ||||||
| LOS, mean, h | 19.6 (SD, 16.01) | 27.0 (SD, 34.51) | <.001 | 20.3 (SE, 1.94) | 27.9 (SE, 1.16) | <.001 |
| LOS, median (IQR), h | 18.8 (7.6-26.4) | 24.2 (7.8-29.7) | .02 | 21.2 (7.5-26.4) | 24.1 (7.8-29.6) | .02 |
| Direct ED discharge | 34 (29) | 261 (30) | .91 | (30) | (30) | .98 |
| Hospital admission | 28 (24) | 204 (23) | .91 | (25) | (23) | .67 |
| Diagnostic testing at index | <.001 | <.001 | ||||
| 0 | 118 (100) | 0 | (100) | (0) | ||
| 1 | 0 | 713 (81) | (0) | (81) | ||
| 2 | 0 | 132 (15) | (0) | (15) | ||
| ≥3 | 0 | 37 (4) | (0) | (4) | ||
| Diagnostic testing at index or follow-up | <.001 | <.001 | ||||
| 0 | 98 (83) | 0 | (83) | (0) | ||
| 1 | 19 (16) | 690 (78) | (16) | (78) | ||
| 2 | 1 (1) | 149 (17) | (1) | (17) | ||
| ≥3 | 0 | 43 (5) | (0) | (5) | ||
| Exercise treadmill test during index visit | 0 | 159 (18) | <.001 | (0) | (18) | <.001 |
| SPECT during index visit | 0 | 174 (20) | <.001 | (0) | (20) | <.001 |
| Stress echocardiography during index visit | 0 | 122 (14) | <.001 | (0) | (14) | <.001 |
| CCTA during index visit | 0 | 474 (54) | <.001 | (0) | (54) | <.001 |
| Invasive coronary angiography | ||||||
| During index visit | 0 | 90 (10) | <.001 | (0) | (10) | <.001 |
| During index or follow-up | 2 (2) | 97 (11) | <.001 | (2) | (11) | .008 |
| PCI | ||||||
| During index hospitalization | 0 | 38 (4) | .02 | (0) | (4) | .01 |
| During follow-up but not during index visit | 2 (2) | 4 (0) | .15 | (2) | (0) | .13 |
| During index or follow-up | 2 (2) | 42 (5) | .15 | (2) | (5) | .16 |
| CABG | ||||||
| During index hospitalization | 0 | 9 (1) | .61 | (0) | (1) | .23 |
| During index or follow-up | 0 | 9 (1) | .61 | (0) | (1) | .23 |
| Return ED visits for chest pain within 28 d | 8 (7) | 25 (3) | .047 | (6) | (3) | .08 |
| Major adverse cardiac events | 2 (2) | 6 (1) | .24 | (2) | (1) | .27 |
| Subgroupc | (n = 69) | (n = 580) | (n = 69) | (n = 580) | ||
| ED costs at index visit, median (IQR), $ | 1405.4 (974.7-2261.5) | 1942.4 (1543.8-3033.1) | <.001 | 1467.3 (1037.9-2261.5) | 1944.8 (1543.2-3060.4) | <.001 |
| Total costs at index visit, median (IQR), $ | 1920.9 (1269.3-2812.5) | 2475.4 (1643.4-4006.9) | <.001 | 2136.8 (1285.9-2989.2) | 2460.2 (1644.6-3980.3) | <.001 |
| Total costs, median (IQR), $ | 2182.2 (1345.8-3223.6) | 2586.0 (1653.9-4118.5) | .002 | 2261.5 (1400.5-3223.6) | 2584.3 (1650.4-4108.8) | .009 |
| Safety Outcomes | ||||||
| Missed ACS within 72 h, No. | 0 | 0 | NA | 0 | 0 | NA |
| Median radiation dose, index visit, (IQR), mSv | 0.0 (0.0-0.0) | 9.7 (0.0-15.3) | <.001 | 0.0 (0.0-0.0) | 9.6 (0.0-15.2) | <.001 |
| Median cumulative radiation dose, (IQR), mSv | 0.0 (0.0-0.0) | 9.9 (0.0-15.5) | <.001 | 0.0 (0.0-0.0) | 9.9 (0.0-15.4) | <.001 |
Abbreviations: ACS, acute coronary syndrome; CABG, coronary artery bypass graft; CCTA, coronary computed tomographic angiography; ED, emergency department; IPTW, inverse probability of treatment weighting; IQR, interquartile range; LOS, length of stay; NA, not applicable; PCI, percutaneous coronary intervention; SPECT, single-photon emission computed tomography myocardial perfusion imaging.
a
All values are given as number (percentage) unless otherwise indicated.
b
Summary statistics derived from the pseudopopulation created after applying IPTW weights.
c
Costs among the subset of 649 patients (69 with clinical evaluation alone and 580 with noninvasive testing) with cost data available, adjusted to 2011 US dollars.