ICD-coding of firearm injuries James Harrison
NISU and Research Center for Injury Studies
Flinders University of South Australia
August 1997 (revised December 1997)
Summary
1. Current coding of deaths and admitted hospital cases due to firearm injury:
does not distinguish
cases die to airguns, etc.;
includes some poorly
defined categories and;
does not correspond to
current Australian firearm license categories.
2. Forthcoming changes in coding (i.e.,
the introduction of ICD-10) will reduce the already limited information on the type of
firearm involved in shooting injuries. Only handguns will be distinguished with any useful
degree of specificity, and these account for a small proportion of cases in Australia.
3. Limited case information restricts
the level of coding that is likely to be practicable without the introduction of special
data collection systems. The extent of information available is being investigated.
4. Revised coding is proposed which:
Provides categories for
airguns and related weapons.
Distinguishes the main
types of firearms that produce injuries in Australia.
Retains compatibility
with versions 9 and 10 of the ICD.
Is no more complex than
the present system (i.e., ICD-9-CM).
Background Shooting injuries account for about 500 deaths per year, and for a similar number
of hospital admissions, in Australia.
Injuries resulting in death or in
admission to a hospital are classified according to the International Classification of
Diseases (ICD). The section of the classification used to code the firearm involved in
producing an injury is the "External Cause" (E-code) chapter. At present (1997),
deaths are coded by the ABS according to the basic WHO edition of the 9th revision of the
ICD (ICD-9), and hospital separations are coded according to the second Australian edition
of the Clinical Modification of the ICD (Australian ICD-9-CM).
The level of detail provided by ICD-9
on the type of firearm involved is similar for each of the main "human intent"
categories distinguished in ICD-9: accident, self-inflicted injury, assault, and
undetermined intent (Table 1). ICD-9 and Australian ICD-9-CM codes for shooting cases are,
at present, identical. The next edition of the classification, ICD-10, provides less
information on the type of firearm than ICD-9, handguns being the only type given a
relatively specific category (Table 2).
Plans are in place to introduce ICD-10
in Australia in the near future. The date of introduction for coding hospital separations
is 1 July 1998. Hospital separations coding will initially use the first Australian
Modification of ICD-10, to be published soon by the National Center for Classification in
Health. (The sections of interest here are the same as in the standard edition of ICD-10.)
Table 1: Coding of firearms in
ICD-9 and Australian ICD-9-CM
Handgun
Shotgun
Hunting rifle
Military firearm
Other
Unspecified
Accident
E922.0
E922.1*
E922.2
E922.3
E922.8
E922.9
Suicide or self-inflicted injury
E955.0
E955.1
E955.2
E955.3
E955.4
Assault
E965.0
E965.1
E965.2
E965.3
E965.4
Legal intervention
-
-
-
-
-
E970
Undetermined intent
E985.0
E985.1
E985.2
E985.3
E985.4
War
-
-
-
-
-
E991 (part)
* "shotgun (automatic)" for
E922.1 (There is no obvious reason for the difference in wording)
"part" means that other types of case are also coded to the category.
"Accidental" injury due to an air rifle or BB gun is coded to E917.9 (Striking
against or struck accidentally by object or person-other)
"Military firearm" and "hunting rifle" are not further defined.
Table 2: Coding of
firearms in ICD-10
Discharge from:
Handgun
Rifle, shotgun, and larger firearm
Other and unspecified firearm*
Accident
W32
W33
W34
Intentional
self-harm
X72
X73
X74
Assault
X93
X94
X95
Undetermined
intent
Y22
Y23
Y24
Legal
intervention
-
-
Y35.0
Operations
of war
-
-
Y36.4 (part)
* Includes "BB gun discharge"
Firearm coding categories chosen for use should be useable in hospital settings. Clinical
information is of two main types
History: a description
provided by the patient, or other witness.
Examination: the
observed nature of the injury (and sometimes the projectile that produced it).
The appearance of firearm wounds
usually provides some information about the nature of the weapon that produced it (e.g.,
rifle vs. shotgun). However, some distinctions that might be of interest for purposes of
monitoring and research cannot be made reliably on the basis of the wound, or examination
of the bullet that produced it (if available). For example, Category C and Category D of
the Australian firearm license categories are distinguished only by the magazine capacity
of weapons. Furthermore, weapons in these two categories are distinguished from weapons in
categories A and B by whether or not they are self-loading (or pump action). Neither of
these characteristics of weapons can be deduced reliably from the clinical features of a
wound.
If such information is to be recorded,
it must be based, solely or in part, on information provided by a witness (including the
injured person, if surviving), or an investigator. Clinical history may or may not provide
information about the nature of the firearm, depending on the condition and knowledge of
the patient and the circumstances of the shooting.
Shooting deaths are generally
investigated by police and assessed and certified by a coroner. About four-fifths are
recorded as suicides and another 5 percent are found to be accidental. One might expect
that the firearm would be readily available for assessment in these cases. Surprisingly,
about 30 percent of firearm suicides and about 40 percent of accidental firearm deaths
between 1979 and 1995 were given the E-code meaning "Firearm other or
unspecified."
Implications The introduction of ICD-10 will reduce the already limited information on the
type of firearm involved in shooting injuries. Only handguns will be distinguished with
any useful degree of specificity. Handguns account for a small minority of shooting cases
in Australia (about 5 percent or less of shooting deaths and less than 20 percent of cases
admitted to a hospital.)
Airgun shootings are not distinguished
under either ICD-9 or ICD-10. "Accidental" airgun shooting moves from the
residual category of "Striking against or struck accidentally by object or person
- other" under ICD-9 to the residual categories for "Discharge from other
and unspecified firearms" under ICD-10. There is no defined place for coding injury
due to gas (not air) or spring powered guns in either edition of ICD.
Two of the categories provided under
ICD-9-CM are poorly defined and pose difficulties for coding and for interpretation.
The ICD categories do not take account
of the current Australian firearm license categories (See
Attachment 1).
The extent, specificity and reliability
of source information is uncertain, and is likely to differ substantially between sites
(e.g., coroner systems vs. hospitals) and cases (e.g., a firearm homicide or
wounding in which the firearm has not been recovered vs. a suicide in which the
firearm is available for inspection.).
Aim
Propose changes to the coding of firearm injuries which will:
Provide categories for
airguns and related weapons.
Retain compatibility
with versions 9 and 10 of the ICD.
Are practicable for use
by hospital coders.
Distinguish the main
types of firearms that produce injuries in Australia.
Take account of the
Australian firearm license categories.
Proposal Code firearm injury cases in Australian hospital separations (preferably also deaths
data) according to the approach shown in Attachment 2. This approach:
Provides categories for
airguns and related weapons.
Distinguishes the main
types of firearms that produce injuries in Australia.
Is no more complex than
the present system (ie ICD-9-CM).
Defines the designated
types of weapon in simple and specific terms. (See
Attachment 3)
Is compatible with
versions 9 and 10 of the ICD. (See Attachments
4 and 5)
Provides codes to enable
the same types of firearms to be distinguished in each of the "intent" sections
of the classification.
This approach provides only limited
compatibility with the Australian firearm license categories. In particular, it does not
draw distinctions based on whether a weapon is self-loading (required to separate Category
C and D weapons from others), nor on magazine capacity (required to distinguish between
Category C and Category D).
Implementation of the approach under
ICD-9-CM would require redefinition of the (currently poorly defined) categories
"hunting rifle" and "military firearm."
Implementation of this model as part of
ICD-10-AM will require a supplementary coding field (i.e., a fourth character). This is
because the ICD-10 Chapter XX classification (the section that covers external causes) has
been structured in a way that provides fewer code categories than the equivalent part of
ICD-9 and leaves little room for expansion within the basic structure.
Further information will be sought on
the extent of information on firearm type that is recorded in medical records. The
findings will guide further steps. These may include efforts to improve the information
about firearms that is recorded, revision of the classification to accommodate
practicalities of clinical practice, and further development of the classification to
specify firearms in terms of the Australian firearm license categories (for example, to
distinguish self-loading and pump-action long-guns from other types)
Attachment 1: Australian Firearm
License Categories in relation to
suggested firearm injury coding categories
-muzzle-loading firearms
-single shot, double barrel and repeating action center fire rifles
-break action shotguns/
rifle combinations
Powder actuated long gun
Shotgun
Category C
(prohibited except for occupational
purposes):
-self-loading rimfire rifles with a magazine
capacity no greater than 10 rounds
-self-loading shotguns with a magazine capacity no greater than 5 rounds
-pump action shotguns with a magazine capacity no greater than 5 rounds
Rifle: small
caliber (.22 or smaller)
Category D
(prohibited except for official purposes):
-self-loading
center fire rifles
-self-loading shotguns and pump action shotguns with a capacity of more than 5 rounds
-self-loading rimfire rifles with a magazine capacity greater than 10 rounds
Rifle: large
caliber (larger than .22)
Category H
(restricted):
-all handguns, including air pistols
Hand gun
Other or unspecified
Attachment 2: Proposed revised coding of firearms
Revised coding of firearms ICD-9
Injury found to be by
Base on this ICD-9 code:
Hand gun
Long gun
Other or unspecified firearm
Not powder actuated
Powder actuated
Shotgun
Rifle: .22 cal. or smaller
Rifle: larger than .22 cal.
Accident
E922
.0
.7
.1
.2
.3
.8, .9
Intentional self-harm
E955
.0
.7
.1
.2
.3
.4
Assault
E965
.0
.7
.1
.2
.3
.4
Legal intervention
E970
.0
.7
.1
.2
.3
.4
Undetermined intent
E985
.0
.7
.1
.2
.3
.4
War
E991
.0
.7
.1
.2
.5
.4
Revised coding of firearms ICD-10
Injury found to be by:
Base on this ICD-9 code:
Hand gun
Long gun
Other or unspecified firearm
Not powder actuated
Powder actuated
Shotgun
Rifle: .22 cal. or smaller
Rifle: larger than .22 cal.
Accident
W34
/1
/2
/3
/4
/5
/9
Intentional
self-harm
X74
/1
/2
/3
/4
/5
/9
Assault
X95
/1
/2
/3
/4
/5
/9
Legal
intervention
Y35.0
/1
/2
/3
/4
/5
/9
Undetermined
intent
Y24
/1
/2
/3
/4
/5
/9
War
Y36.4
/1
/2
/3
/4
/5
/9
NOTES:
Both tables "Handgun": includes air pistol and shortened ("sawn-off") long
guns.
"Nonpowder" actuated long guns: includes air rifles and other gas or spring
operated long guns.
"Shotgun" and "rifle" include pump-action and self-loading types. Table 3 Use the values in the body of the table as 4th digits for the E-codes shown in the
second column.
Alter the coding rule for accidental injury due to an air rifle: use E922.7, not E917.9
(part). Injury due to war operations by bullets and fragments (E991): alter use of E991.0,
E991.1 and E991.2 as shown in Table 3. Retain standard use of E991.3 and E991.9. Table 4 Use the values in the body of the table as an additional digit for the codes shown
in the second column. This could be an additional character or a separate field.
Standard ICD-10 codes W32, X72, X93 and Y22 could be used in place of W34/1, X74/1, X95/1
and Y24/1. ICD-10 codes W33, X73, X94, and Y23 are not required.
Attachment 3: Suggested wording of category
descriptions
Firearm types
Short name
Inclusions
Exclusions
Handgun
Handgun
Powder actuated handgun Air, gas, or spring
actuated handgun
Sawn-off shotgun or rifle
Long gun
Not powder actuated
Air rifle
Air, gas, or spring
actuated long gun
"BB gun"
Powder actuated
Shotgun
Shotgun
Pump action shotgun
Rifle <= .22
Rifle small
caliber
Any rifle of these
calibers
Rifle > .22
Rifle large
caliber
Any rifle of these
calibers
Other or unspecified firearm
Other or unspecified
Attachment 4: Mapping revised firearm category codes to
standard ICD-9-CM
Rubric
E-code
Modified
E-code
STRUCK
BY OBJ/PERSON NEC (part)*
E917.9 (part)
E922.7
HANDGUN
ACCIDENT&&&
E922.0
E922.0
SHOTGUN
ACCIDENT&&&
E922.1
E922.1
HUNTING
RIFLE ACCIDENT&**
E922.2
E922.2
MILITARY
FIREARM ACCID&***
E922.3
E922.3
FIREARM
ACCIDENT NEC&&&
E922.8
E922.8
FIREARM
ACCIDENT NOS&&&
E922.9
E922.9
SUICIDE-HANDGUN
E955.0
E955.0
SUICIDE-SHOTGUN
E955.1
E955.1
SUICIDE-HUNTING
RIFLE&&**
E955.2
E955.2
SUICIDE-MILITARY
FIREARM***
E955.3
E955.3
SUICIDE-FIREARM
NEC
E955.4
E955.4
ASSAULT-HANDGUN
E965.0
E965.0
ASSAULT-SHOTGUN
E965.1
E965.1
ASSAULT-HUNTING
RIFLE&&**
E965.2
E965.2
ASSAULT-MILITARY
WEAPON***
E965.3
E965.3
ASSAULT-FIREARM
NEC
E965.4
E965.4
LEGAL
INTERVENT-FIREARM
E970
E970/0 to 4, 7
UNDETERMIN
CIRC-HANDGUN
E985.0
E985.0
UNDETERMIN
CIRC-SHOTGUN
E985.1
E985.1
UNDET
CIRC-HUNTING RIFLE**
E985.2
E985.2
UNDET
CIRC-MILITARY ARMS***
E985.3
E985.3
UNDETER
CIRC-FIREARM NEC
E985.4
E985.4
WAR
INJURY: RUBBER BULLET
E991.0
-
WAR
INJURY:PELLETS (RIFLE
E991.1
E991.1
WAR
INJURY:BULLET NEC&&
E991.2
E991/2,5,6,7
WAR
INJ:ANTIPERSON BOMB
E991.3
-
WAR
INJ:FRAGMENTS NEC&&
E991.9
E991.9
??
??
E955.7, E965.7, E985.7
*Airgun cases
** Redefined. Model A: "Rifle, .22 or smaller"; Model B: "Rifle, not
self-loading"
*** Redefined. Model A: "Rifle, larger than .22"; Model B: "Rifle,
self-loading"
Attachment 5: Mapping proposed revised firearm codes to
standard ICD-10
Rubric
Ch. XX code
Modified Ch. XX Code
Handgun
discharge
W32
Not used
Rifle, shotgun,
and larger firearm discharge
W33
Not used
Discharge from
other and unspecified firearm
W34
W34/1,2,3,4,5,9
intentional
self-harm by handgun discharge
X72
Not used
Intentional
self-harm by rifle, shotgun, and larger firearm discharge
X73
Not used
Intentional
self-harm by other and unspecified firearm discharge
X74
X74/1,2,3,4,5,9
Assault by
handgun discharge
X93
Not used
Assault by
rifle, shotgun, and larger firearm discharge
X94
Not used
Assault by other
and unspecified firearm discharge
X95
X95/1,2,3,4,5,9
Handgun
discharge, undetermined intent
Y22
Not used
Rifle, shotgun,
and larger firearm discharge, undetermined inten
Y23
Not used
Discharge from
other and unspecified firearm, undetermined inten
Y24
Y24/1,2,3,4,5,9
Legal
intervention involving firearm discharge
Y35.0
Y35.0/1,2,3,4,5,9
War operations
involving firearm discharge and other forms of conventional warfare (part)*