Table 1.
Baseline characteristics of the 2759 participants.
| Median age (IQR) | 40 (30–50) |
| Male | 1428 (51.8) |
| Race | |
| White | 1128 (40.9) |
| African American | 690 (25.0) |
| Asian | 125 (4.5) |
| Native American | 38 (1.4) |
| Pacific Islander | 6 (0.2) |
| More than one | 88 (3.2) |
| Hispanic | 668 (24.2) |
| Refused | 16 (0.6) |
| Median pain level (IQR) | 9 (7–10) |
| Duration of pain since onset (hours) | |
| 1–2 | 445 (16.1) |
| 3–6 | 465 (16.9) |
| 7–12 | 270 (9.8) |
| 13–24 | 284 (10.3) |
| 25–48 | 292 (10.6) |
| >48 | 980 (35.5) |
| Refused | 23 (0.8) |
| Nausea | 1750 (63.4) |
| Prior diagnosis of kidney stone | 1149 (41.7) |
| Prior urologic intervention | 375 (13.6) |
| Costo-vertebral angle tenderness | 1448 (52.4) |
| Hematuria on urinalysis | |
| <3 rbc/hpf | 949 (34.4) |
| >3 rbc/hpf | 1215 (44.0) |
| Too numerous to count | 256 (9.3) |
| Not obtained | 339 (12.2) |
| WBC on urinalysis | |
| <50 wbc/hpf | 2160 (78.3) |
| >50 wbc/hpf | 192 (6.9) |
| Too numerous to count | 56 (2.0) |
| Not obtained | 351 (12.7) |
| The presence of hydronephrosis on imaging | |
| None | 1897 (68.8) |
| Present | 802 (29.1) |
| Not reported | 58 (2.1) |
| Admitted to hospital | 236 (8.6) |
| Urologic intervention | |
| Received urologic intervention at baseline | 52 (1.9) |
| Received urologic intervention by 30 days | 143 (5.2) |