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. 2018 Nov 25;8(11):e022090. doi: 10.1136/bmjopen-2018-022090

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.