Survival outcomes and causes of death of trauma patients: Examining the concordance of external causes of

morbidity and mortality data

Presenter: Kirsten McKenzieResearch Team: Sue Walker, Leanne Aitken, Andrea Besenyei,

Bridget Allison, Deirdre McDonaghAffiliations: National Centre for Classification in Health, QUT

Queensland Trauma Registry, UQ

Background

• Mortality as trauma outcome – Key indicator of trauma system effectiveness

• Deaths post-discharge – Related to trauma?

• Morbidity and mortality ICD coded data for trauma outcome research

• External cause as UCOD vs MCOD

Background (Continued)

• Quality coded data affected by:– Quality of source documentation– Accuracy of coding

• Lack detail documentation overuse of ‘dump’ codes (eg. Unspecified accident)

• Coding accuracy relies on adherence to ICD coding rules and guidelines

Research Questions

1. What were the survival outcomes of trauma patients?

2. Was trauma recorded on the death certificate of patients who died post-discharge?

3. If trauma was recorded, was there concordance in the coded data between the morbidity and mortality collections for trauma patients who died post-discharge?

Methodology

• Participants = 1672 trauma patients• Procedure:

– Data matched to NDI using probabilistic matching

– Matched cases formed sample for this research

Methodology (Continued)

• Cases categorised as:– Dying from medical condition with no trauma

recorded– Dying from medical condition with trauma as MCOD– Dying from trauma (trauma as UCOD)

• Comparison of coded data: – Codes grouped and compared based on WHO lists– Expert coder ranked code match:

• More defined external cause in NDI than hospital• Less defined external cause in NDI than hospital• No match between NDI and hospital external cause

Results

• 8.4% one year mortality rate (Total N=1672):– 3.6% Died in hospital (n=60)

– 1.0% Died <31 days post-discharge (n=17)

– 0.5% Died 31-60 days post-discharge (n=8)

– 3.3% Died 61 days-1 yr post-discharge (n=55)

Survival Rates

• Survival rates by cause:– 84.3% Falls (n=604) – 94.8% MVA (n=346)– 98.8% Machinery (n=166)– 97.2% Homicide (n=109)– 88.5% Self-Harm (n=87)

• Survival rate by age: – 96.8% Age<65yrs (n=1206)– 78.1% Age>65yrs (n=466)

Survival outcomes from most common causes of injuries

0%

2%

4%

6%

8%

10%

12%

14%

Hospital death Post-dischargedeath

Falls (n=604)

MVA (n=346)

Machinery (n=166)

Homicide (n=109)

Self-Harm (n=87)

Survival outcomes by age groups

0%

2%

4%

6%

8%

10%

12%

Age<65yrs Age>65yrs

Hospital death

<30days

31-60 days

61 days-1 year

Post-discharge deaths:

Medical vs Traumatic UCOD

• Over 10% trauma patients who died in hospital had no trauma coded in NDI

• Deaths up to 60 days post-discharge – All but 2 cases aged over 65 years– Almost 70% of trauma patients who

died within 60 days post discharge with injuries due to fall had no trauma coded in NDI

Causes of injuries by UCOD for hospital death and post-discharge <60 days

0

20

40

60

80

100

MedicalUCOD

TraumaMCOD

TraumaUCOD

Falls (n=44)

MVA (n=15)

Self-Harm (n=8)

Concordance of external cause in morbidity and mortality data

• Deaths <60 days post-discharge:– Causes of injuries did not match for ¾ cases– Only one falls case had fall recorded in NDI– All unmatched falls cases due to ‘dump’ code

use in NDI

Discussion

• 2/3 post-discharge deaths <60 days had no trauma coded in NDI

• When trauma was coded, ¾ post-discharge deaths <60 days had different causes in NDI than hospital records

• Where differences found, NDI usually had poorly defined causes of injury compared to hospital records

Recommendations• Using hospital data or mortality data alone

would not sufficiently capture and describe all cases who die following hospitalisation for trauma

• Better quality information for trauma outcome research if significant recent trauma is reflected on death certificate (even if only as MCOD)

• Mortality rates alone are crude indicators - multiple data issues need to be considered when examining mortality outcomes

Further Information

Dr Kirsten McKenzieResearch Fellow

National Centre for Classification in Health

k.mckenzie@qut.edu.auPh. 07 3864 9753