Introduction
Methods
Data source
Study population
Use of CT over three-year following the incident injury
Potential predictors
Statistical analysis
Results
Cohort characteristics
N | % | |
---|---|---|
Sex | ||
Male | 12,531 | 58.16 |
Female | 9013 | 41.84 |
Age group | ||
18–29 years | 7481 | 34.72 |
30–44 years | 5606 | 26.02 |
45–64 years | 4908 | 22.78 |
65 + years | 3549 | 16.47 |
SEIFA | ||
Least disadvantage | 9285 | 43.10 |
Less disadvantage | 3577 | 16.60 |
Moderate disadvantage | 4901 | 22.75 |
High disadvantage | 2340 | 10.86 |
Highest disadvantage | 1276 | 5.92 |
Unknown | 165 | 0.77 |
ARIA | ||
Major cities | 20,150 | 93.53 |
Inner regional areas | 427 | 1.98 |
Outer regional areas | 445 | 2.07 |
Remote areas | 306 | 1.42 |
Very remote areas | 131 | 0.61 |
Unknown | 85 | 0.39 |
Anatomical areas of injury | ||
Head | 4077 | 18.92 |
Neck | 699 | 3.24 |
Thorax | 1037 | 4.81 |
Abdomen | 1271 | 5.90 |
Extremity | 13,928 | 64.65 |
Multiple injury | 532 | 2.47 |
Injury with hospital admission | ||
No | 14,870 | 69.02 |
Yes | 6674 | 30.98 |
Group of external causes of injury | ||
Transport/pedestrian | 2,348 | 10.90 |
Fall | 5556 | 25.79 |
Force$ | 7302 | 33.89 |
Others/unknown$$ | 6338 | 29.42 |
Severity of injury | ||
Mild > 99%SRR) | 20,022 | 92.94 |
Moderate 94.1–99% SRR) | 846 | 3.93 |
Severe/very severe < = 95% SRR) | 676 | 3.14 |
Presentation day | ||
Weekday | 13,330 | 61.87 |
Weekend/PH | 8214 | 38.13 |
ED shift | ||
Day 8:00–15:59) | 10,232 | 47.49 |
Evening 16:00–23:59) | 8169 | 37.92 |
Night 0:00–7:59) | 3143 | 14.59 |
Mode of arrival | ||
Private transport | 15,459 | 71.76 |
Ambulance | 5766 | 26.76 |
Others | 319 | 1.48 |
Median Length of hospital stay (days) | 0 | 0–1 |
History of comorbidities | ||
None | 11,592 | 53.81 |
1–2 comorbidities | 4798 | 22.27 |
3 + comorbidities | 5154 | 23.92 |
History of hospital admission (1 year prior) | ||
No hospitalisation | 13,050 | 60.57 |
1–2 hospitalisations | 6982 | 32.41 |
3 + hospitalisation | 1512 | 7.02 |
History of CT scan (1 year prior) | ||
None | 19,722 | 91.54 |
1 + CT scans | 1822 | 8.46 |
CT scan use status during 3-year follow-up | ||
No CT use | 14,453 | 67.10 |
At least one CT scanning | 7091 | 32.90 |
Latent classes of CT use over three-year follow-up
CT use classes | N (%) | Total no. of CT (N, %) | Average number of CT in 3 years (Mean (95%CI))/median (IQR) | Days between the first and the last CT |
---|---|---|---|---|
1- Consistently high CT use | 181 (2.6) | 1425 (9.6) | 7.9 (7.29–8.45)/ 7 (5–9) | Mean (SD): 646.1 (269.3) Median (IQR): 659 (397) |
2- Low CT use | 3621 (51.1) | 6111 (41.2) | 1.7 (1.64–1.73)/ 1 (1–2) | Mean (SD): 358.7 (275.5) Median (IQR): 315 (455) |
3- Temporally high CT use | 3289 (46.3) | 7297 (49.2) | 2.2 (2.16–2.28)/ 2 (1–3) | Mean (SD): 456.2 (366.8) Median (IQR): 430 (720) |
7091 (100) | 14,833 (100) | 2.1 (2.05–2.14) |
Factors predicting classes of CT use
Characteristics | No CT use | CT use | p-value | ||||||
---|---|---|---|---|---|---|---|---|---|
Class 1 | Class 2 | Class 3 | |||||||
n | (%) | n | % | n | % | n | % | ||
Sex | |||||||||
Male | 8713 | 60.3 | 90 | 49.7 | 1826 | 50.4 | 1902 | 57.8 | < 0.001 |
Female | 5740 | 39.7 | 91 | 50.3 | 1795 | 49.6 | 1387 | 42.2 | |
Age group | |||||||||
18–29 years | 6052 | 41.9 | 6 | 3.3 | 705 | 19.5 | 718 | 21.8 | < 0.001 |
30–44 years | 4080 | 28.2 | 15 | 8.3 | 803 | 22.2 | 708 | 21.5 | |
45–64 years | 2978 | 20.6 | 46 | 25.4 | 1047 | 28.9 | 837 | 25.5 | |
65 + years | 1343 | 9.3 | 114 | 63.0 | 1066 | 29.4 | 1,026 | 31.2 | |
SEIFA | |||||||||
Least disadvantage | 6380 | 44.1 | 73 | 40.3 | 1460 | 40.3 | 1372 | 41.7 | < 0.001 |
Less disadvantage | 2418 | 16.7 | 28 | 15.5 | 613 | 16.9 | 518 | 15.8 | |
Moderate disadvantage | 3265 | 22.6 | 44 | 24.3 | 896 | 24.7 | 696 | 21.2 | |
High disadvantage | 1470 | 10.2 | 21 | 11.6 | 406 | 11.2 | 443 | 13.5 | |
Highest disadvantage | 814 | 5.6 | 12 | 6.6 | 219 | 6.1 | 231 | 7.0 | |
ARIA* | |||||||||
Major cities | 13590 | 94.0 | 169 | 93.4 | 3,422 | 94.5 | 2969 | 90.3 | < 0.001 |
Inner regional areas | 277 | 1.9 | * | 61 | 1.7 | * | |||
Outer regional areas | 282 | 2.0 | * | 66 | 1.8 | * | |||
Remote areas | 175 | 1.2 | * | 46 | 1.3 | * | |||
Very remote areas | 79 | 0.6 | * | 13 | 0.4 | * | |||
Anatomical areas of injury | |||||||||
Head/neck | 2893 | 20.0 | 48 | 26.5 | 626 | 17.3 | 1209 | 36.8 | |
Thorax | 613 | 4.2 | 15 | 8.3 | 202 | 5.6 | 207 | 6.3 | |
Abdomen | 685 | 4.7 | 21 | 11.6 | 239 | 6.6 | 326 | 9.9 | |
Extremity | 9,973 | 69.0 | 88 | 48.6 | 2473 | 68.3 | 1394 | 42.4 | |
Multiple injury | 289 | 2.0 | 9 | 5.0 | 81 | 2.2 | 153 | 4.7 | |
Admitted to hospital | |||||||||
No | 11264 | 77.9 | 72 | 39.8 | 2529 | 69.8 | 1005 | 30.6 | < 0.001 |
Yes | 3189 | 22.1 | 109 | 60.2 | 1,092 | 30.2 | 2284 | 69.4 | |
External cause of injury | |||||||||
Transport/pedestrian | 1329 | 9.2 | 23 | 12.7 | 311 | 8.6 | 685 | 20.8 | < 0.001 |
Fall | 3233 | 22.4 | 78 | 43.1 | 1073 | 29.6 | 1172 | 35.6 | |
Force | 5639 | 39.0 | 22 | 12.2 | 1053 | 29.1 | 588 | 17.9 | |
Others/unknown | 4252 | 29.4 | 58 | 32.0 | 1184 | 32.7 | 844 | 25.7 | |
Severity of injury | |||||||||
Mild (> 99%SRR) | 13921 | 96.3 | 139 | 76.8 | 3390 | 93.6 | 2572 | 78.2 | < 0.001 |
Moderate (94.1–99% SRR) | 285 | 2.0 | 24 | 13.3 | 124 | 3.4 | 413 | 12.6 | |
Severe/very severe (< = 95% SRR) | 247 | 1.7 | 18 | 9.9 | 107 | 3.0 | 304 | 9.2 | |
Date of presentation | |||||||||
Weekday | 8815 | 61.0 | 130 | 71.8 | 2343 | 64.7 | 2042 | 62.1 | < 0.001 |
Weekend/PH | 5638 | 39.0 | 51 | 28.2 | 1278 | 35.3 | 1247 | 37.9 | |
ED shifts | |||||||||
Day (8:00–15:59) | 6791 | 47.0 | 91 | 50.3 | 1,879 | 51.9 | 1,471 | 44.7 | < 0.001 |
Evening (16:00–23:59) | 5533 | 38.3 | 75 | 41.4 | 1,293 | 35.7 | 1,268 | 38.6 | |
Night (0:00–7:59) | 2129 | 14.7 | 15 | 8.3 | 449 | 12.4 | 550 | 16.7 | |
Mode of arrival | |||||||||
Private transport | 11421 | 79.0 | 77 | 42.5 | 2566 | 70.9 | 1395 | 42.4 | < 0.001 |
Ambulance | 3032 | 21 | 104 | 57 | 1055 | 29 | 1894 | 58 | |
Median length of stay of an index event (days) | 0 | 0–0 | 1 | 0–5 | 0 | 0–1 | 2 | 0–5 | < 0.001 |
History of comorbidity | |||||||||
None | 8822 | 61.0 | 25 | 13.8 | 1320 | 36.5 | 1425 | 43.3 | < 0.001 |
1–2 comorbidities | 3152 | 21.8 | 30 | 16.6 | 905 | 25.0 | 711 | 21.6 | |
3 + comorbidities | 2479 | 17.2 | 126 | 69.6 | 1396 | 38.5 | 1153 | 35.1 | |
History of hospitalisation | |||||||||
No hospitalisation | 10097 | 69.9 | 39 | 21.6 | 1,978 | 54.6 | 936 | 28.5 | < 0.001 |
1–2 hospitalisations | 3842 | 26.6 | 71 | 39.2 | 1284 | 35.5 | 1785 | 54.3 | |
3 + hospitalisation | 514 | 3.6 | 71 | 39.2 | 359 | 9.9 | 568 | 17.3 | |
History of CT scan | |||||||||
None | 13 735 | 95.0 | 105 | 58.0 | 3060 | 84.5 | 2822 | 85.8 | < 0.001 |
1 + CT scans | 718 | 5.0 | 76 | 42.0 | 561 | 15.5 | 467 | 14.2 |
Characteristics | IRR | 95%CI |
---|---|---|
Female | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.74 | (0.54; 1.02) |
Low CT use Class 2 | 1.08 | (0.99; 1.17) |
Temporally high CT use Class 3 | 0.81*** | (0.73; 0.89) |
30–44 years old | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 2.90* | (1.10; 7.61) |
Low CT use Class 2 | 1.59*** | (1.42; 1.78) |
Temporally high CT use Class 3 | 1.33*** | (1.18; 1.51) |
45–64 years old | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 9.54*** | (3.89; 23.3) |
Low CT use Class 2 | 2.58*** | (2.30; 2.90) |
Temporally high CT use Class 3 | 1.90*** | (1.67; 2.16) |
65 + years old | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 18.8*** | (7.53; 47.2) |
Low CT use Class 2 | 4.33*** | (3.76; 4.99) |
Temporally high CT use Class 3 | 2.10*** | (1.79; 2.47) |
Less disadvantage SEIFA | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.03 | (0.65; 1.63) |
Low CT use Class 2 | 1.12 | (1.00; 1.25) |
Temporally high CT use Class 3 | 0.97 | (0.85; 1.10) |
Moderate disadvantage SEIFA | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.20 | (0.81; 1.78) |
Low CT use Class 2 | 1.21*** | (1.09; 1.33) |
Temporally high CT use Class 3 | 0.97 | (0.86; 1.08) |
High disadvantage SEIFA | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.00 | (0.59; 1.70) |
Low CT use Class 2 | 1.18* | (1.03; 1.36) |
Temporally high CT use Class 3 | 0.99 | (0.85; 1.15) |
Highest disadvantage SEIFA | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.55 | (0.80; 3.02) |
Low CT use Class 2 | 1.28** | (1.08; 1.53) |
Temporally high CT use Class 3 | 1.04 | (0.86; 1.26) |
Inner regional areas | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.90 | (0.31; 2.61) |
Low CT use Class 2 | 0.80 | (0.59; 1.08) |
Temporally high CT use Class 3 | 0.84 | (0.63; 1.13) |
Outer regional areas | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.67 | (0.20; 2.26) |
Low CT use Class 2 | 0.83 | (0.62; 1.12) |
Temporally high CT use Class 3 | 0.73* | (0.55; 0.97) |
Remote areas | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.99 | (0.32; 3.04) |
Low CT use Class 2 | 0.84 | (0.58; 1.20) |
Temporally high CT use Class 3 | 0.91 | (0.66; 1.24) |
Very remote areas | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.00E-06 | (0; 0.00) |
Low CT use Class 2 | 0.63 | (0.33; 1.17) |
Temporally high CT use Class 3 | 0.99 | (0.61; 1.60) |
Head injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 3.19*** | (2.16; 4.72) |
Low CT use Class 2 | 1.00 | (0.90; 1.12) |
Temporally high CT use Class 3 | 3.91*** | (3.50; 4.36) |
Neck injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.46 | (0.51; 4.18) |
Low CT use Class 2 | 1.08 | (0.85; 1.38) |
Temporally high CT use Class 3 | 3.59*** | (2.90; 4.44) |
Thorax injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.82 | (1.00; 3.34) |
Low CT use Class 2 | 1.10 | (0.92; 1.32) |
Temporally high CT use Class 3 | 1.89*** | (1.56; 2.30) |
Abdomen injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.94* | (1.12; 3.34) |
Low CT use Class 2 | 1.17 | (0.98; 1.38) |
Temporally high CT use Class 3 | 2.29*** | (1.92; 2.72) |
Multiple injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 2.77** | (1.30; 5.93) |
Low CT use Class 2 | 1.08 | (0.82; 1.42) |
Temporally high CT use Class 3 | 2.16*** | (1.70; 2.76) |
Admitted to hospital | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.59* | (0.38; 0.93) |
Low CT use Class 2 | 0.61*** | (0.53; 0.71) |
Temporally high CT use Class 3 | 2.39*** | (2.05; 2.78) |
External cause of injury: Transport/pedestrian | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.97* | (1.14; 3.41) |
Low CT use Class 2 | 1.15 | (0.98; 1.35) |
Temporally high CT use Class 3 | 1.44*** | (1.24; 1.67) |
External cause of injury: Force | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.74 | (0.43; 1.27) |
Low CT use Class 2 | 0.97 | (0.87; 1.09) |
Temporally high CT use Class 3 | 0.50*** | (0.43; 0.57) |
Severity of injury: Moderate 94.1–99% SRR | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.57 | (0.92; 2.67) |
Low CT use Class 2 | 0.93 | (0.73; 1.19) |
Temporally high CT use Class 3 | 1.51*** | (1.25; 1.81) |
Severity of injury: Severe/very severe < = 95% SRR | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.48* | (0.26; 0.88) |
Low CT use Class 2 | 0.49*** | (0.37; 0.64) |
Temporally high CT use Class 3 | 0.89 | (0.72; 1.10) |
Date of presentation: Weekend/PH | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.76 | (0.54; 1.07) |
Low CT use Class 2 | 0.95 | (0.88; 1.03) |
Temporally high CT use Class 3 | 1.05 | (0.96; 1.15) |
ED shifts: Evening 16:00–23:59 | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.16 | (0.84; 1.62) |
Low CT use Class 2 | 0.94 | (0.86; 1.02) |
Temporally high CT use Class 3 | 1.04 | (0.95; 1.15) |
ED shifts: Night 0:00–7:59 | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 0.61 | (0.34; 1.08) |
Low CT use Class 2 | 0.94 | (0.83; 1.06) |
Temporally high CT use Class 3 | 0.95 | (0.83; 1.08) |
Model of arrival: Ambulance | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.22 | (0.84; 1.78) |
Low CT use Class 2 | 1.01 | (0.91; 1.13) |
Temporally high CT use Class 3 | 1.44*** | (1.29; 1.60) |
Length of stay | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.03*** | (1.02; 1.04) |
Low CT use Class 2 | 0.99 | (0.97; 1.00) |
Temporally high CT use Class 3 | 1.03*** | (1.02; 1.04) |
History of comorbidity: 1–2 comorbidities | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.66 | (0.95; 2.89) |
Low CT use Class 2 | 1.43*** | (1.30; 1.59) |
Temporally high CT use Class 3 | 1.11 | (0.99; 1.24) |
History of comorbidity: 3 + comorbidities | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 3.05*** | (1.87; 4.98) |
Low CT use Class 2 | 1.79*** | (1.60; 1.99) |
Temporally high CT use Class 3 | 1.33*** | (1.18; 1.51) |
History of 1–2 hospitalisations | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.70* | (1.06; 2.73) |
Low CT use Class 2 | 1.16** | (1.04; 1.30) |
Temporally high CT use Class 3 | 1.34*** | (1.17; 1.54) |
History of 3 + hospitalisation | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 2.43** | (1.38; 4.27) |
Low CT use Class 2 | 1.03 | (0.85; 1.24) |
Temporally high CT use Class 3 | 1.18 | (0.96; 1.45) |
History of CT scan | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 4.95*** | (3.52; 6.97) |
Low CT use Class 2 | 2.10*** | (1.84; 2.39) |
Temporally high CT use Class 3 | 1.86*** | (1.60; 2.16) |
Number of ED presentations related to injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 4.95*** | (1.56; 1.98) |
Low CT use Class 2 | 2.10*** | (1.40; 1.55) |
Temporally high CT use Class 3 | 1.22*** | (1.15; 1.30) |
Number of hospitalisations related to injury | ||
No CT use | Ref | |
Consistently high CT use Class 1 | 1.78*** | (1.61; 1.97) |
Low CT use Class 2 | 1.51*** | (1.43; 1.59) |
Temporally high CT use Class 3 | 1.47*** | (1.39; 1.55) |