# Presentation: 724356

## Injury:what should we count?

**John Langley**
**Megan Davies**

## Background

- For public hospital discharges NZ has counted anything with an E code for the purposes of describing the injury problem!

## All public hospital discharges withE code: 1998  (n=105,862)

- Non injury diagnosis for the principal diagnosis accounts for 36% (n=38,434) of all E coded discharges.
- Of these 41% (n=15,735) did not have injury as secondary or subsequent diagnosis.
- Vast majority (80%) of 15,735 cases had     E codes identifying iatrogenic factors (e.g. adverse effects of drugs)

## What is in the ICD Injury and Poisoning chapter?

- Fractures, Dislocations, Sprains/strains, internal injury, open wounds, injury to blood vessels, late effects of injury, superficial injury, contusions, crushings, effects of foreign bodies, burns, injury to nerves and spinal cord, traumatic complications, poisonings, toxic effects. (800-994).
- Certain adverse effects not elsewhere classified (995).
- Complications of surgical and medical care not elsewhere classified (996-999).

## One view of dealing with medical injury

- Conditions in the range 995-999 should be excluded from the definition of injury for most studies because they have different aetiology and means of prevention.

## Response to that strategy

- Neither is sufficient grounds for exclusion.
- Besides which the argument does not stand close scrutiny:
- aspects of aetiology may be the same! (needle injury)
- Prevention strategies may be different – but so too are they for suicide compared with unintentional injury
- Rather the decision should be based on whether they meet the theoretical definition of injury.

## Theoretical Definition of Injury

- Damage to the body produced by acute exposure  to thermal, mechanical, electrical, or chemical energy, or the absence of such essentials as heat or oxygen.
- Damage due to some chronic low exposures (e.g. carpal tunnel syndrome) is also included by some.

## 996-999 Complications of surgical and medical care not elsewhere classified: non-injury?

- 996.0 Mechanical complication of cardiac device, implant of and graft
- 997.1 Cardiac complications (e.g . Cardiac arrest during a procedure)
- 998.0 Postoperative infection
- 999.7 Generalized vaccinia

## 996-999 Complications of surgical and medical care not elsewhere classified: injury?

- 997.0 Central nervous system complications (e.g anoxic brain damage during procedure)
- 998.2 Accidental puncture or laceration during a procedure
- 998.4 Foreign body accidentally left during procedure

## Excluding all medical injuries is the equivalent of “ throwing the baby out with the bathwater”

## Significance of medical injuries for estimates of incidence and determining priorities: NZ experience: 1999 hospital inpatients

- Traditional injury: (800-994): 	40,924	83%
- Medical injury: (995-999):	  8,167	17%
- All “injury”: (800-999):	 	 49,091	100%

## Hospital Discharge Data

**Availability **
**about 40 states**
**Health Dept may not have access**
**Comparability**
** ****types of hospitals reporting**
** ****numbers of diagnostic fields**
** ****data elements**
**E codes**
**confidentiality**

## Hospital Discharge Data

**Quality**
**Completeness of hospitals reporting**
**Ability to detect multiple hospitalizations for same injury**
**Cross-border hospitalizations**
**Other out-of-state hospitalizations (eg, in winter residents of FL or AZ)**

## Hospital Discharge Data

**Quality**
**Percentage of injury hospitalizations with external cause coding**
**hospital**
**diagnosis**
**demographics**
**season**
**Accuracy of coding (external cause and nature of injury)**

## Hospital Discharge Data

**Ad hoc working group**
**case definition for injury hospitalization**
** ****calculating percentage of external cause coding**
**Injury Surveillance Workgroup 3**
**Recommendations for the Use of HDD for Injury Surveillance**

## Injury Hospitalization

**Hospital**
**Non-federal**
**Acute-care**
**Inpatient facility**

## Injury Hospitalization

**Principal diagnosis injury**
**Includes **
**late effects**
**re-admissions**
**transfers**
**deaths in hospital**
**Excludes **
**adverse effects of therapeutic drugs and medical/surgical care and their late effects**

## Injury Hospitalization

**Includes**
**800-909.2, 909.4, 909.9**
**910-994.9**
**995.5-995.59**
**995.80-995.85**

## Injury Hospitalization

**Excludes**
**<800**
**909.3, 909.5**
**995.0-995.4, 995.6-995.7, 995.86, 995.89**
**996-999**

## Injuries (?) outside the ICD injury and poisoning chapter

- 717 Internal derangement of knee
- 718 Other derangement of joint
- 724 Other and unspecified disorders of  	  back

## If there is no discernible physical damage to the body why are we counting the following as “injury”?

- Rape ?
- Foreign bodies ?
- Back pain?
-    None of these fit a commonly accepted theoretical definition of injury.

## Theoretical Definition of Injury

- Damage to the body produced by acute exposure  to thermal, mechanical, electrical,or chemical energy, or the absence of such essentials as heat or oxygen.
- Damage due to some chronic low exposures (e.g. carpal tunnel syndrome) is also included by some.

## Conclusion

- We need to revisit our theoretical definition of injury.
- Having done the above we need to reconsider our operational definition of injury (in terms of ICD diagnosis codes).
- 	These issues will become increasingly important as we move to intra and inter country comparisons of non-fatal injury.

## Injury Prevention Research Unit

**Injury Prevention Research Unit**
**is supported by:**