Table 1. Baseline characteristics of study patients with abdominal pain at the emergency department.
| Characteristics | US (n = 392) | No US (n = 391) | ||
| Mean (SD) | n (%) | Mean (SD) | n (%) | |
| Age | 47 (20) | 48 (19) | ||
| Sex | ||||
| Male | 160 (40.8) | 171 (43.7) | ||
| Female | 232 (59.2) | 220 (56.3) | ||
| Length | 172 (9) | 172 (10) | ||
| Weight | 73 (16) | 73 (16) | ||
| Body mass index | 24.8 (4.5) | 24.8 (4.3) | ||
| Abdominal-related co-morbidity | 76 (19.4) | 78 (19.9) | ||
| Co-morbidity related to heart or diabetes | 66 (16.8) | 74 (18.9) | ||
| History of abdominal malignancy | 6 (1.5) | 12 (3.1) | ||
| History of other malignancy | 11 (2.8) | 14 (3.6) | ||
| Other co-morbidity | 132 (33.7) | 123 (31.5) | ||
| Admission for abdominal pain within1 year | 124 (32.0) | 137 (35.3) | ||
| Referral for admission | 92 (24.4) | 126 (32.9) | ||
| Duration of pain | ||||
| 0–8 h | 44 (14.8) | 43 (14.4) | ||
| 8–24 h | 99 (33.2) | 97 (32.4) | ||
| >24 h | 147 (49.3) | 151 (50.5) | ||
| Cannot answer | 8 (2.7) | 8 (2.7) | ||
| Actual VAS (of pain) | 4.3 (2.8) | 4.4 (2.6) | ||
| Maximal recall VAS (of pain) | 7.6 (2.6) | 7.6 (1.8) | ||
| Temperature | 37.0 (0.8) | 37.0 (0.7) | ||
| Affected general condition | 90 (23.3) | 74 (19.1) | ||
| Tenderness | 338 (86.4) | 347 (89.2) | ||
| Rigidity | 51 (13.1) | 49 (12.6) | ||
| Palpable mass | 23 (5.9) | 29 (7.5) | ||
US, ultrasound; VAS, visual analogue scale (scale 0–10 where 0 represents no pain at all and 10 represents unbearable pain).