Results of multivariate logistic regression analysis with tracheostomy as dependent variable and coalition military casualty (including US and UK), ISS grouping, mandible fracture and no treatment of mandible fracture as independent variables
| Tracheostomy | OR | SE | Z | P>|z| | 95% CI | |
| Treatment in US MTF | 3.033696 | 0.5472023 | 6.15 | 0 | 2.13028 | 4.320235 |
| Coalition military | 0.4257238 | 0.0292904 | −12.41 | 0 | 0.3720181 | 0.4871828 |
| Mandible fracture present | 8.021444 | 0.6257567 | 26.69 | 0 | 6.884143 | 9.346633 |
| No treatment of mandible fracture | 0.7424999 | 0.0770788 | −2.87 | 0.004 | 0.6058057 | 0.9100379 |
| ISS group 3–15 | 0.1356279 | 0.0106448 | −25.45 | 0 | 0.1162899 | 0.1581816 |
| ISS group 16–24 | 0.4933107 | 0.0419693 | −8.31 | 0 | 0.4175447 | 0.5828248 |
| ISS group 25–75 | 1 | (omitted) | ||||
ISS, Injury Severity Score; MTF, medical treatment facilities.