TABLE 1:
Comparison of Study Variables Between Sites
| Variable, Level | Site 1 (n = 7813) | Site 2 (n = 2776) | All (n = 10,589) | p |
|---|---|---|---|---|
| Patient location | < .001 | |||
| ED | 685 (8.8) | 14 (0.5) | 699 (6.7) | |
| Inpatient | 1154 (14.8) | 875 (32.4) | 2029 (19.3) | |
| Outpatient | 5974 (76.5) | 1809 (67.0) | 7783 (74.0) | |
| Total no. | 7813 | 2698 | 10,511 | |
| Sonographer | ||||
| Volume (examinations) | < .001 | |||
| < 50 | 493 (6.4) | 530 (19.2) | 1023 (9.8) | |
| 50–500 | 5327 (69.4) | 2237 (80.8) | 7564 (72.5) | |
| > 500 | 1853 (24.1) | 0 (0.0) | 1853 (17.7) | |
| Total no. | 7673 | 2767 | 10,440 | |
| Experience (y) | < .001 | |||
| 0–3 | 1129 (14.9) | 55 (2.0) | 1184 (11.4) | |
| 4–10 | 2744 (36.1) | 912 (33.0) | 3656 (35.3) | |
| > 10 | 3718 (49.0) | 1800 (65.1) | 5518 (53.3) | |
| Total no. | 7591 | 2767 | 10,358 | |
| Reader | ||||
| Practice pattern | < .001 | |||
| Ultrasound | 3113 (39.9) | 997 (35.9) | 4110 (38.8) | |
| Abdominal | 4003 (51.2) | 342 (12.3) | 4345 (41.0) | |
| Community | 695 (8.9) | 1382 (49.8) | 2077 (19.6) | |
| Interventional | 0 (0.0) | 54 (1.9) | 54 (0.5) | |
| Volume (examinations) | < .001 | |||
| < 50 | 66 (0.8) | 131 (4.7) | 197 (1.9) | |
| 50–500 | 3976 (50.9) | 2161 (77.9) | 6137 (58.0) | |
| > 500 | 3769 (48.3) | 483 (17.4) | 4252 (40.2) | |
| Experience (y) | < .001 | |||
| 0–3 | 125 (1.6) | 16 (0.6) | 141 (1.3) | |
| 4–10 | 1394 (17.8) | 410 (14.8) | 1804 (17.0) | |
| > 10 | 6292 (80.6) | 2349 (84.6) | 8641 (81.6) | |
| Total no. | 7811 | 2775 | 10,586 | |
| Median (95% CI) time in examination room (min) (n = 8588) | 31.0 (16.0–77.0) | 34.0 (6.0–94.0) | 31.0 (16.0–79.0) | < .001a |
Note—Unless otherwise indicated, values are expressed as number of examinations, with percentages in parentheses. Counts do not sum to 10,589 for individual variables because of missing data. Percentages represent distributions across subsets for each site (i.e., down columns). p values were calculated using a chi-square test unless otherwise indicated. ED = emergency department.
a
Computed using Wilcoxon rank-sum test.