Baseline patient data for 2001–2007
| Clipping | Coiling | P | |
|---|---|---|---|
| No. | 5219 | 5405 | |
| Mean age (SD) | 53.3 (11.6) | 56.1 (13.2) | <.0001 |
| Race (No.) (%) | |||
| White | 2695 (76.2) | 2840 (78.3) | .06 |
| Black | 361 (10.2) | 359 (9.9) | |
| Hispanic | 335 (9.5) | 283 (7.8) | |
| Asian | 55 (1.6) | 70 (1.9) | |
| Native American | 18 (0.5) | 16 (0.4) | |
| Other | 75 (0.2) | 61 (1.7) | |
| Female (No.) (%) | 3878 (74.6) | 4064 (75.5) | .27 |
| Hospital volume stratification (No.) (%) | |||
| ≤5 Cases per year | 1237 (23.7) | 499 (9.2) | <.00001 |
| 6–20 Cases per year | 1996 (38.2) | 1632 (30.2) | |
| 21–44 Cases per year | 944 (18.1) | 1453 (26.9) | |
| ≥45 Cases per year | 1042 (20.0) | 1821 (33.7) | |
| Physician volume stratification (No.) (%) | |||
| ≤5 Cases per year | 1494 (49.2) | 1241 (35.8) | <.0001 |
| 6–10 Cases per year | 432 (14.2) | 488 (14.1) | |
| 11–20 Cases per year | 439 (14.5) | 611 (17.6) | |
| ≥21 Cases per year | 670 (22.1) | 1124 (32.5) |