Table 1.
Data characteristics
| Characteristics | Early surgery | Late surgery |
|---|---|---|
| N | 8387 | 8620 |
| Negative | 8189 (97.6%) | 8189 (95.0%) |
| Positive | 198 (2.4%) | 431 (5.0%) |
| Average days between LIRE enrollment and decompression surgery | 34.3 | 168 |
| Age | 57 | 57.2 |
| Gender | ||
| Female | 4713 (56.2%) | 4845 (56.2%) |
| Race | ||
| White | 5317 (63.4%) | 5502 (63.8%) |
| Black | 991 (11.8%) | 1007 (11.7%) |
| Unknown | 990 (11.8%) | 1000 (11.6%) |
| Asian | 928 (11.1%) | 948 (11.0%) |
| Pacific Islander | 50 (0.6%) | 51 (0.6%) |
| Other | 27 (0.3%) | 26 (0.3%) |
| Multiracial | 17 (0.2%) | 19 (0.2%) |
| Ethnicity | ||
| Not available | 5945 (70.9%) | 6129 (71.1%) |
| Not Hispanic | 1233 (14.7%) | 1263 (14.7%) |
| Hispanic | 1209 (14.4%) | 1228 (14.2%) |
| Image type | ||
| MRI | 5810 (69.3%) | 5980 (69.4%) |
| X-ray | 2517 (30.0%) | 2576 (29.9%) |
| CT | 60 (0.7%) | 64 (0.7%) |
| System | ||
| Kaiser Permanente | 7071 (84.3%) | 7274 (84.4%) |
| Henry Ford | 654 (7.8%) | 657 (7.6%) |
| Group Health | 486 (5.8%) | 517 (6.0%) |
| Mayo Clinic | 176 (2.1%) | 172 (2.0%) |