Table 6.
Variance decomposition statistics by selected injury mechanisms
| Hospital ICC (95% CI) |
Neighbourhood ICC (95% CI) |
Residual ICC (95% CI) |
Patients (n) | |
| Falls* | ||||
| Mortality, unadjusted | 2.9% (1.0 to 4.7) | 0.2% (−0.2 to 0.7) | 96.9% (94.6 to 99.3) | 117 454 |
| Mortality, adjusted for casemix | 2.4% (2.4 to 2.4) | 0.0% (0.0 to 0.0) | 97.6% (97.6 to 97.6) | 117 454 |
| Length of stay, unadjusted | 19.3% (11.2 to 26.2) | 0.2% (0.1 to 0.3) | 80.5% (73.6 to 88.7) | 112 954 |
| Length of stay, adjusted for casemix | 13.5% (7.3 to 18.9) | 0.1% (0.06 to 0.2) | 86.4% (80.9 to 92.6) | 112 915 |
| Total charges, unadjusted | 22.5% (10.9 to 31.7) | 0.09% (0.02 to 0.2) | 77.4 (67.2 to 89.1) | 76 409 |
| Total charges, adjusted for casemix | 24.0% (11.1 to 33.8) | 0.04% (−0.006 to 0.1) | 75.9 (66.1 to 88.8) | 76 385 |
| Firearms† | ||||
| Mortality, unadjusted | 20.2% (15.9 to 32.9) | 0.8% (−2.9 to 4.2) | 79.1% (64.5 to 101.9) | 6498 |
| Mortality, adjusted for casemix | 16.4% (−0.6 to 28.5) | 1.5% (−2.2 to 4.9) | 82.1% (68.1 to 103.3) | 6498 |
| Length of stay, unadjusted | 20.3% (6.7 to 30.4) | 0.0% (0.0 to 0.0) | 79.7% (69.6 to 93.3) | 2970 |
| Length of stay, adjusted for casemix | 12.6% (4.9 to 19.7) | 0.2% (−0.2 to 0.8) | 87.1% (79.8 to 95.2) | 5857 |
| Total charges, unadjusted | 12.2% (5.0 to 18.8) | 0.2% (−0.2 to 0.6) | 87.6% (80.8 to 95.1) | 5858 |
| Total charges, adjusted for casemix | 21.3% (5.8 to 33.6) | 0.07% (−0.4 to 0.8) | 78.6% (66.2 to 94.7) | 2970 |
| Motor vehicle‡ | ||||
| Mortality, unadjusted | 4.7% (−0.8 to 9.7) | 1.1% (−1.1 to 3.4) | 94.2% (87.3 to 101.9) | 22 604 |
| Mortality, adjusted for casemix | 2.7% (−0.4 to 5.7) | 1.6% (−1.0 to 4.2) | 95.6% (90.4 to 101.5) | 22 604 |
| Length of stay, unadjusted | 13.0% (6.0 to 19.2) | 0.3% (0.1 to 0.6) | 86.7% (80.3 to 93.8) | 21 082 |
| Length of stay, adjusted for casemix | 14.5% (7.0 to 21.2) | 0.2% (−0.002 to 0.4) | 85.3% (78.6 to 93.0) | 21 057 |
| Total charges, unadjusted | 19.6% (10.0 to 27.7) | 0.6% (0.2 to 1.2) | 79.8% (71.5 to 89.7) | 12 430 |
| Total charges, adjusted for casemix | 18.3% (8.9 to 26.4) | 0.5% (0.2 to 1.0) | 81.1% (73.0 to 90.8) | 12 418 |
*Hospital, n=65; Zip code, n=213.
†Hospital, n=52; Zip code, n=178.
‡Hospital, n=65; Zip code, n=211.
Unadjusted models include random effects only. Adjusted models include fixed effects for patient age, Injury Severity Score, mechanism of injury and number of patient comorbidities.
ICC, intraclass correlation coefficient.