130510 Serious Injury Inpatient Analysis Specification for the Injury Observatory For

130510 Serious injury inpatient analysis specification for the Injury Observatory for Britain and Ireland (IOBI)

The purpose of this paper is to develop a specification for comparative analysis of inpatient data for the five countries within IOBI. The inpatient analyses to be undertaken will focus specifically on very serious injuries, comprising a set of ICD 10 codes that identify injuries which from medical experience should be admitted anywhere. By focusing on serious injuries that should almost always be admitted it is possible to minimise the likely variation in the results between countries caused by varying admission thresholds.

Definition of serious injury

Two different sets of ICD 10 codes will be used to identify very serious injuries.

(i)  Set 1 (Appendix A) will comprise those ICD 10 codes used as part of the serious admitted injury analyses conducted by IOBI in 2009 (http://www.injuryobservatory.net/iobi_inpatient_analysis.html). This will allow comparisons to be made between the number of serious injuries reported in the 2009 analysis and the number reported as part of this current analysis. This list of serious injuries was defined by Professor Ronan Lyons, a medical expert in the area of injuries.

(ii)  Set 2 (Appendix B) will comprise those ICD 10 codes used in the serious injury outcome indicators that were developed to monitor the New Zealand Injury Prevention Strategy (NZIPS) [Statistics New Zealand (2011). Serious injury outcome indicators – technical report. Wellington: Statistics New Zealand]. This report used the International Classification of Diseases-based Injury Severity Score (ICISS) to define a serious injury. Specifically, serious non-fatal injury cases were defined as hospitalisations with an ICISS score of less than or equal to 0.941. This is equivalent to selecting patients whose injuries give them a survival probability of 94.1% or worse – in other words, a probability of death (at admission) of at least 5.9%. This represents around 15% of all injury discharges (Cryer, C, Langley, J, & Stephenson, S (2004). Developing valid injury indicators. A report for the New Zealand Injury Prevention Strategy (Injury Prevention Research Unit Occasional Report OR 049). Dunedin: University of Otago).

Not every single ICD 10 code identified as defining a serious injury in the NZIPS report will be used as part of this IOBI analysis. Certain ICD 10 codes have been excluded, either due to them not being considered serious enough following further inspection by Professor Ronan Lyons, or because they require the presence of a 5th character ICD 10 code, which tends not to be frequently recorded in the UK. Also due to the inability to code to 5 characters some ICD 10 codes listed in the NZIPS report are only included in this IOBI analysis at the 4 character level. A list of the ICD 10 codes used in the NZIPS report but excluded for this IOBI analysis is provided in Appendix D, whilst a list of the ICD 10 codes used in the NZIPS report but changed to 4 characters for this IOBI analysis is provided in Appendix E.

It should additionally be noted that several ICD 10 codes have been added to the NZIPS ICD 10 list that will be used in this IOBI analysis. These codes, listed in Appendix F, have been included because it is illogical for them to be left out given the seriousness of the injury.

Unit of hospital activity

Inpatient spells will be used by all countries as the unit of hospital activity in this analysis. A caveat will be added to the final output file warning all readers that the way in which episodes of care are amalgamated to spells within the healthcare system of each country is likely to vary, and that, consequently, caution should be exercised when interpreting the cross-country results.

Time period

Inpatient spells will be searched for during the period 01.01.2011 and 31.12.2011

Type of admission

Only emergency hospital admissions will be considered.

Dealing with admissions with zero length of stay

All admissions will be considered irrespective of length. Research undertaken in Wales in 2009 showed that excluding hospitalisations with a zero length of stay led to 4% of deaths also being excluded (090825 inpatient analysis specification 7th draft). Admissions with a zero length of stay were included in both the 2009 IOBI analysis and the New Zealand ICISS analysis (page 18 of Developing valid injury indicators report).

Diagnosis criteria

For the repeat of the IOBI analysis undertaken in 2009 the S/T codes listed in Appendix A should be searched for in any diagnosis position. For the new analysis based on the ICD 10 codes derived in New Zealand the S/T codes listed in Appendix B should also be searched for in any diagnosis position. For both of the analyses, the external cause/intent categories should be searched for in any diagnostic position. In addition, for both of the analyses an inpatient admission will only be counted if it has both the S/T diagnosis AND the external cause/intent diagnosis.

By insisting that an admission must be associated with both an S/T and external cause/intent diagnosis it follows that the final counts will be influenced by the completeness of diagnosis coding. i.e. if there are a large number of admissions with an S/T code but no external cause/intent code, and vice-versa. For this reason it is important for coding completeness to be assessed within each country. To achieve this each country should count the number of emergency inpatient admissions taking place in 2011 which have an S/T ICD 10 code in any diagnosis position but which don’t have an V/W/X/Y ICD 10 code in any diagnostic position, and vice-versa.

Cause/intent categories reported

The same external cause/intent categories will be used as in the 2009 analysis. An all injury figure will also be reported. The external cause categories are:

-  Cut/pierce

-  Drowning

-  Falls

-  Fire/hot object or substance

-  Firearm

-  Motor vehicle traffic crash (MVTC)

-  Poisoning

-  Struck by/against

-  Other unspecified

The intent categories are:

-  Unintentional

-  Self-harm

-  Assault

-  Other/unspecified/undetermined

The ICD 10 codes that will be used to identify the above categories are listed in Appendix C.

Order of precedence

An order of precedence ranking should be used to determine the primary cause and/or intent in cases where admissions were assigned multiple cause and intent categories.

The precedence list that should be applied in terms of the external cause of the admissions is: 1 – MVTC; 2 – Fall; 3 – Cut; 4 – Drowning, 5 – Fire; 6 – Firearm; 7 – Struck by/against; 8 – Poisoning; 9 – Other and unspecified.

With regards to the intent associated with each admission the order of precedence ranking that should be used is: 1 – Self-harm; 2 – Assault; 3 – Other/unspecified/undetermined; 4 – Unintentional.

The use of these precedence lists is considered necessary to ensure that only the most likely cause/intent applicable to each admission is counted. However, their use additionally means that the true incidence of admissions associated with specific causes/intents further down the rankings may be underreported.

Output

The required output comprises counts of serious inpatient admissions by 5 year age group and gender. In addition, mid-year population estimates for 2011 by 5 year age group and gender need to be provided. The counts of inpatient admissions and population estimates will then be used to derive European Age Standardised Rates (EASR).

Note: the UK census in 2011 & re-basing of population denominators will need to be taken into account when comparing the results of this analysis with the previous IOBI analysis undertaken in 2009.

Appendix A: Set 1 list of ICD 10 codes to be applied in this IOBI analysis based on those ICD 10 codes used as part of the serious admitted injury analyses conducted by IOBI in 2009 (http://www.injuryobservatory.net/iobi_inpatient_analysis.html).

The following S/T ICD 10 codes were used as part of the serious admitted injury analyses conducted by IOBI in 2009 (http://www.injuryobservatory.net/iobi_inpatient_analysis.html). They will be used again during this IOBI analysis in order to allow comparisons to be made between the number of serious injuries reported in the 2009 analysis and the number reported as part of this current analysis. This list of serious injuries was defined by Professor Ronan Lyons, a medical expert in the area of injuries.

The following ICD 10 codes should be searched for in any diagnostic position:

S02 (excluding 02.2, 02.5) Fracture of skull and facial bones

S06 Intracranial injury

S12 Fracture of neck

S14 Injury of nerves and spinal cord at neck level

S22.0, 22.1, 22.2 Fracture of thoracic vertebra and sternum

S22.5 Flail chest

S24 Injury of nerves and spinal cord at thorax level

S25, 26, 27, 28 Injury of blood vessels of thorax, injury of heart, injury of other unspecified intrathoracic organs, crushing injury of thorax and traumatic amputation of part of thorax

S32 (excluding 32.2) Fracture of lumbar spine and pelvis

S34 (34.0 to 34.5) Injury of nerves and lumbar spinal cord at abdomen, lower back and pelvis level.

S35 Injury of blood vessels at abdomen, lower back and pelvis level

S36, 37, 38 Injury of intra-abdominal organs, injury of pelvic organs, crushing injury and traumatic amputation of part of abdomen, lower back and pelvis

S48, 58, 68 Traumatic amputation of shoulder and upper arm, forearm, wrist and hand

S72 (72.0 to 72.3) Fracture of femur (neck and shaft)

S73.0 Dislocation of hip

S78, 88, 98 Traumatic amputation of hip and thigh, lower leg, ankle and foot

T02 Fractures involving multiple body regions

T04 Crushing injuries involving multiple body regions

T05 Traumatic amputations involving multiple body regions

T06 Other injuries involving multiple body regions, not elsewhere classified

Appendix B: Set 2 list of ICD 10 codes to be applied in this IOBI analysis based on the ICD 10 codes used in the New Zealand serious injury outcome indicators report [Cryer, C, Langley, J, & Stephenson, S (2004). Developing valid injury indicators. A report for the New Zealand Injury Prevention Strategy (Injury Prevention Research Unit Occasional Report OR 049). Dunedin: University of Otago]

The following ICD 10 codes were used in the serious injury outcome indicators that were developed to monitor the New Zealand Injury Prevention Strategy (NZIPS) [Statistics New Zealand (2011). Serious injury outcome indicators – technical report. Wellington: Statistics New Zealand]. As mentioned on page 1 not every single ICD 10 code used in the above report will be applied in this IOBI analysis. Certain ICD 10 codes have been excluded from the list below, either due to them not being considered serious enough following further inspection by Professor Ronan Lyons, or because they require the presence of a 5th character ICD 10 code, which tends not to be frequently recorded in the UK (Appendix D). Also due to the inability to code to 5 characters some ICD 10 codes in the below list are only included at the 4 character level (Appendix E).

The following ICD 10 codes should be searched for in any diagnostic position.

S020 Fracture of vault of skull

S021 Fracture of base of skull

S026 Fracture of mandible, part unspecified

S027 Multiple fractures involving skull and facial bones

S029 Fracture of skull and facial bones, part unspecified

S040 Injury of optic nerve and pathways

S061 Traumatic cerebral oedema

S062 Diffuse brain injury

S063 Focal brain injury

S064 Epidural haemorrhage

S065 Traumatic subdural haemorrhage

S066 Traumatic subarachnoid haemorrhage

S068 Other intracranial injuries

S069 Intracranial injury, unspecified

S070 Crushing injury of face

S110 Open wound involving larynx and trachea

S120 Fracture of first cervical vertebra

S121 Fracture of second cervical vertebra

S122 Fracture of other specified cervical vertebra

S129 Fracture of neck, part unspecified

S131 Dislocation of cervical vertebrae

S140 Concussion and oedema of cervical spinal cord

S141 Other and unspecified injuries of cervical spinal cord

S142 Injury of nerve root of cervical spine

S150 Injury of carotid artery

S151 Injury of vertebral artery

S153 Injury of internal jugular vein

S158 Injury of other blood vessels at neck level

S179 Crushing injury of neck, part unspecified

S220 Fracture of thoracic vertebra

S224 Multiple rib fractures

S225 Flail chest

S231 Dislocation of thoracic vertebrae

S241 Other and unspecified injuries of thoracic spinal cord

S243 Injury of peripheral nerves of thorax

S250 Injury of thoracic aorta

S251 Injury of innominate or subclavian artery

S252 Injury of superior vena cava

S254 Injury of pulmonary blood vessels

S255 Injury of intercostal blood vessels

S257 Injury of multiple blood vessels of thorax

S268 Other injuries of heart

S269 Injury of heart, unspecified

S271 Traumatic haemothorax

S272 Traumatic haemopneumothorax

S273 Other injuries of lung

S278 Injury of other specified intrathoracic organs

S279 Injury of unspecified intrathoracic organ

S318 Open wound of other and unspecified parts of abdomen

S320 Fracture of lumbar vertebra

S328 Fracture of other and unspecified parts of lumbar spine and pelvis

S332 Dislocation of sacroiliac and sacrococcygeal joint

S351 Injury of inferior vena cava

S352 Injury of coeliac or mesenteric artery

S354 Injury of renal blood vessels

S358 Injury of other blood vessels at abdomen, lower back and pelvis level

S359 Injury of unspecified blood vessel at abdomen, lower back and pelvis level

S360 Injury of spleen

S361 Injury of liver or gallbladder

S362 Injury of pancreas

S365 Injury of colon

S367 Injury of multiple intra-abdominal organs

S368 Injury of other intra-abdominal organs

S369 Injury of unspecified intra-abdominal organ

S370 Injury of kidney

S373 Injury of urethra

S379 Injury of unspecified pelvic organ

S427 Multiple fractures of clavicle, scapula and humerus

S429 Fracture of shoulder girdle, part unspecified

S443 Injury of axillary nerve

S450 Injury of axillary artery

S481 Traumatic amputation at level between shoulder and elbow

S489 Traumatic amputation of shoulder and upper arm, level unspecified

S720 Fracture of neck of femur

S721 Pertrochanteric fracture

S722 Subtrochanteric fracture

S723 Fracture of shaft of femur

S724 Fracture of lower end of femur

S727 Multiple fractures of femur

S728 Fractures of other parts of femur