Table 6.
Most common traumatic brain injury (TBI) international classification of diseases, ninth revision (ICD-9) codes at outpatient encounters.
| Exposed | Unexposed | RR | 95% CI | |
|---|---|---|---|---|
| First 12 months | n = 559 | n = 455 | ||
| Concussion | 53.67% | 45.71% | 1.17 | 1.03–1.33 |
| Head injury, unspecified | 37.21% | 46.37% | 0.80 | 0.69–0.93 |
| Post-concussion syndrome | 14.67% | 12.75% | 1.15 | 0.84–1.57 |
| Years 2–7 | n = 3,398 | n = 2,596 | ||
| Concussion | 57.83% | 55.32% | 1.05 | 0.99–1.09 |
| Post-concussion syndrome | 29.27% | 26.25% | 1.11 | 1.02–1.21 |
| Late effect of intracranial injury w/out mention of skull fracture | 19.75% | 14.75% | 1.34 | 1.19–1.50 |
| Years 8–14 | n = 487 | n = 380 | ||
| Concussion | 46.41% | 48.16% | 0.96 | 0.84–1.11 |
| Intracranial injury nos | 33.88% | 27.89% | 1.21 | 0.99–1.49 |
| Late effect of intracranial injury without mention of skull fracture | 33.06% | 35.26% | 0.94 | 0.78–1.13 |
Categories are not mutually exclusive.