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Table 5 False negative rates for various indices by outcome in population groups

From: Australian Injury Comorbidity Indices (AICIs) to predict burden and readmission among hospital-admitted injury patients

Outcome Number of patients in initial cohort Number (%) of patients with outcome Number (%) of patients classified as not having the outcome when likely to have using the;
outcome-specific binary index parsimonious index CCI ECM
  Adults (> = 15 years) - all injuries
At least one overnight stay 140,094 99,275 (70.9) 30,093/99273 (30.3) 30,059/99273 (30.3) 30,868/99273 (31.1) 30,008/99219 (30.2)
All-cause 30-day readmission 136,670 16,672 (12.2) 6833/16672 (41.0) 6803/16672 (40.8) 6828/16672 (41.0) 6790/16672 (40.7)
Non-planned 30-day readmission 136,670 11,150 (8.2) 4440/11150 (39.8) 4449/11150 (39.9) 4527/11150 (40.6) 4437/11150 (39.8)
  Children (< 15 years) - all injuries
At least one overnight stay 21,240 11,062 (52.1) 3537/21194 (32.1) 3537/21194 (32.1) 3829/21238 (34.6) 3827/21189 (34.8)
All-cause 30-day readmission 21,196 1274 (6.0) 486/21179 (38.2) 487/21179 (38.2) 491/21183 (38.5) 474/21141 (37.2)
Non-planned 30-day readmission 21,196 804 (3.8) 303/21046 (37.7) 303/21056 (37.7) 303/21101 (37.7) 343/21006 (42.7)
  Patients 65 years and above
At least one overnight stay 49,820 41,600 (83.5) 11,092/49525 (26.9) 11,163/49525 (27.0) 11,806/49820 (28.4) 11,097/49480 (26.9)
All-cause 30-day readmission 47,968 7948 (16.6) 3589/47968 (45.2) 3546/47968 (44.6) 3609/47968 (45.4) 3484 /47961 (43.8)
Non-planned 30-day readmission 47,968 5424 (11.3) 2378/47968 (43.8) 2373/47968 (43.8) 2381/47968 (43.9) 2287/47961 (42.2)
  Adult males
At least one overnight stay 76,211 51,046 (67.0) 16,312/76109 (32.0) 16,336/76109 (32.1) 16,670/76210 (32.7) 16,334/76034 (32.1)
All-cause 30-day readmission 74,206 8359 (11.3) 3280/74205 (39.2) 3304/74205 (39.5) 3272/74205 (39.1) 3262/74205 (39.0)
Non-planned 30-day readmission 74,206 5626 (7.6) 2157/74205 (38.3) 2133/74205 (37.9) 2143/74205 (38.1) 2088/74205 (37.1)
  Adult females
At least one overnight stay 63,883 48,229 (75.5) 14,205/63702 (29.6) 14,187/63702 (29.5) 14,594/63882 (30.3) 14,138/63675 (29.4)
All-cause 30-day readmission 62,464 8313 (13.3) 3623/62463 (43.6) 3602/62463 (43.3) 3588/62463 (43.2) 3570/62459 (42.9)
Non-planned 30-day readmission 62,464 5524 (8.8) 2351/62463 (42.6) 2292/62463 (41.5) 2346/62463 (42.5) 2301/62459 (41.7)
  Adults with non-severe injuries
At least one overnight stay 119,916 79,942 (66.7) 26,684/119915 (33.4) 26,885/119915 (33.6) 27,455/119915 (34.3) 26,672/119889 (33.4)
All-cause 30-day readmissiona       
Non-planned 30-day readmission 117,951 9030 (7.7) 3560/117950 (39.4) 3553/117950 (39.4) 3639/117950 (40.3) 3570/117950 (39.5)
  Adults with intracranial injuryb
At least one overnight stay 5456 4093 (75.0) 883/5190 (23.1) 886/5190 (23.2) 915/5456 (22.4) 882/5136 (23.4)
All-cause 30-day readmission 5026 633 (12.6) 235/5026 (37.1) 237/5026 (37.4) 236/5026 (37.3) 231/5026 (36.5)
Non-planned 30-day readmission 5026 492 (9.8) 184/5026 (37.4) 180/5026 (36.6) 181/5026 (36.8) 188/5018 (38.2)
  Patients with hip fractures 45 years and abovec
At least one overnight stay 161,334 110,337 (68.4) 36,536/161332 (33.1) 36,714/161332 (33.3) 37,331/161332 (33.8) 36,497/161277 (33.1)
All-cause 30-day readmission 7400 1115 (15.1) 452/7400 (40.5) 519/7400 (46.6) 491/7400 (44.0) 464/7394 (41.6)
Non-planned 30-day readmission 7400 818 (11.1) 382/7400 (46.7) 393/7400 (48.0) 306/7400 (37.4) 344/7394 (42.1)
  Adults with blunt traumad
At least one overnight stay 94,698 71,004 (75.0) 19,844/94629 (28.0) 19,924/94629 (28.1) 20,331/94696 (28.6) 19,973/94545 (28.2)
All-cause 30-day readmission 92,217 12,169 (13.2) 5174/92204 (42.5) 5210/92204 (42.8) 5201/92204 (42.7) 5069/ 92,204 (41.7)
Non-planned 30-day readmission 92,217 8313 (9.0) 3441/92204 (41.4) 3423/92204 (41.2) 3451/92204 (41.5) 3380/92177 (40.7)
  Adults with penetrating traumae
At least one overnight stay 13,313 7937 (59.6) 3165/13262 (40.1) 3161/13262 (40.1) 3245/13313 (40.9) 3143/13256 (39.9)
All-cause 30-day readmission 13,075 1058 (8.1) 460/13071 (43.5) 466/13071 (44.1) 461/13071 (43.6) 456/13045 (43.2)
Non-planned 30-day readmission 13,075 651 (5.0) 270/13058 (41.5) 270/13059 (41.5) 291/13059 (44.7) 275/13017 (42.2)
  NSW validation (age > =15 years)
At least one overnight stay 201,791 146,177 (72.4) 46,323/146176 (31.7) 46,336/146176 (31.7) 46,670/146176 (31.9) 46,102/146176 (31.5)
All-cause 30-day readmission 193,522 28,237 (14.6) 11,911/28237 (42.2) 11,815/28237 (41.8) 11,956/28237 (42.3) 11,999/28237 (42.5)
Non-planned 30-day readmission 193,522 15,988 (8.3) 6209/15988 (38.8) 6269/15988 (39.2) 6321/15988 (39.5) 6308/15988 (39.5)
  WA validation (age > =15 years)
At least one overnight stay 71,771 51,296 (71.5) 17,114/51296 (33.4) 17,181/51296 (33.5) 17,409/51296 (33.9) 17,072/51296 (33.3)
All-cause 30-day readmission 69,164 9132 (13.2) 3592/9132 (39.3) 3662/9132 (40.1) 3647/ 9132 (39.9) 3623/9132 (39.7)
Non-planned 30-day readmission 69,164 5684 (8.2) 2093/5684 (36.8) 2098/5684 (36.9) 2162/5684 (38.0) 2081/5684 (36.6)
  1. Notes
  2. Cut-off for classification tables set to maximise sensitivity and specificity
  3. a. Injury severity was not found to be associated with all-cause 30-day readmission, therefore no validation was carried out in this subgroup
  4. b. Intracranial injury = ICD-10-AM codes S06.00 - S06.9
  5. c. Hip fractures = ICD-10 codes S72.0 - S72.2
  6. d. Blunt trauma = ICD-10 codes V00-V99, W00-W19, W20-W24, W30-W31, W50-W52, X50, X79-X82, Y00-Y05 and Y29-Y32
  7. e. Penetrating trauma = ICD-10 codes W53, W54, W55, W57, W58, W59, W25, W26, W27, W28, W29, W45, W32, W34, X72-X74, X78, X93-X95, X99, Y22-Y24 andY28
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