Lethality of suicide methods

A A Elnour J Harrison

Research Centre for Injury

Studies, Flinders University,

Adelaide, SA, Australia

OutlineOutline

Introduction

Methods

Results

Discussion

Comments

Luo Xiaomin

Zhang Xia

IntroductionIntroduction

Suicide is a major public health problem.

Establishing the effectiveness of preventive

interventions is challenging.

Availability of suicide means can influence

suicide occurrence. Restricting availability

may decrease overall suicide rates.

IntroductionIntroduction

Published data are lacking on case fatality.

Examining case fatality by sex, age, and

time will improve understanding of suicidal

behavior and might aid prevention.

IntroductionIntroduction

Objectives Quantify the lethality of suicide methods

used in Australia in the period 1 July 1993 to 30 June 2003

Examine method-specific case fatality by age and sex

Identify changes in case fatality during the study period

OutlineOutline

Methods

Results

Discussion

Comments

MethodsMethods

Data source

Completed suicides (deaths) : National

Mortality Files (n=24 194) Australian Bureau of Statistics(ABS)

Cases resulting in hospitalization due to

intentional self-harm : Australia’s National

Hospital Morbidity Database (n=177 967) Australian Institute of Health and Welfare (AIHW)

MethodsMethods

1. Firearms

2. Hanging, Strangulation and Suffocation (Hanging/Suffocation)

3. Poisoning by gases and vapors (Gases/Vapors)

4. Poisoning by and exposure to solid or liquid substances (Drugs/Poisons)

5. Drowning and Submersion

6. Jumping from a height

7. Cutting and piercing by sharp objects (sharp objects)

8. Lying or jumping before a moving object

9. Crashing a motor vehicle

10. Other and unspecified

Specified 10 types of method of self-harm in terms of ICD-9 and ICD-10.

MethodsMethods

Definition ‘‘Fatal episodes’’ of self-harm means

completed suicides ‘‘Non-fatal episodes’’ of self-harm means

cases recorded as being due to intentional self-harm which, based on the available data,were survived

‘‘Total episodes’’ were estimated as the sum of these.

MethodsMethods

Double counting of cases recorded in both sources was controlled by omitting fatal hospital cases from estimates of episodes of self-harm.

Case lethality for each method was estimated by dividing suicide deaths for that method by total episodes involving the same suicide method.

Confidence intervals assume a Poisson distribution of cases, hence used Poisson regression and non-parametric tests.

OutlineOutline

Results

Discussion

Comments

Case fatalityCase fatality

Overall, of the total episodes (n=202 161), 12% resulted in death (24 194).

Total episodes of intentional self-harm increased

Fatal episodes increased and then decreased

Non-fatal episodes increased

Method-specific ratesMethod-specific rates Firearms were the most lethal suicide means

(90%) followed by hanging (83%)

*Total, fatal, and non-fatal episodes are annual average rates per 100 000 population for the 10-year period 1 July 1993 to 30 June 2003.

Figure 2 Method-specific case fatality by sex, Australia, Figure 2 Method-specific case fatality by sex, Australia, 1 July 1993 to 30 June 2003.1 July 1993 to 30 June 2003.

For each suicide method, case fatality was higher in males.

Figure 3 Method-specific case fatality by age, Australia, Figure 3 Method-specific case fatality by age, Australia, 1 July 1993 to 30 June 2003.1 July 1993 to 30 June 2003.

For each suicide method, case fatality was higher in older age groups.

Figure 4 Method-specific time trends in case fatality, Figure 4 Method-specific time trends in case fatality, Australia, 1 July 1993 to 30 June 2003.Australia, 1 July 1993 to 30 June 2003.

Case fatality for firearm cases changed little over time, but declined for self-harm by hanging/suffocation, poisoning, sharp objects, and crashing a motor vehicle.

OutlineOutline

Discussion

Comments

Review the results brieflyReview the results briefly

Overall case fatality was 12%. Case fatality was higher in males and older age

groups. Firearms were the most lethal suicide

means(90%). Hanging is the second method(83%).

Rates of suicide such as firearms declined over time, but those involving hanging rose.

Case fatality for firearm cases changed little, but other self-harm means declined.

Discussion---Discussion---advantageadvantage

Broaden the view by using both hospital data (non-fatal episodes) and death data (fatal episodes).

Study the lethality of the suicide methods and the case fatality varies over time.

Discussion 1Discussion 1

The rate of non-fatal episodes increased through the period, whereas the rate of fatal episodes rose until 1997–98, then fell.

Methods of self-harm changed (with an overall decrease in case fatality)

Changes in retrieval or treatment (increase in survival from some types of self-harm)

Changes in information (eg, changes in case ascertainment).

Discussion 2Discussion 2

Was the rise in suicide by hanging causally related to the decline in suicide by firearms?

The relationship between the increase in suicides by hanging and the decrease in firearm related suicides is ambiguous.

its occurrence requires more than observing opposing trends.

Discussion 3Discussion 3

Hanging rose dramatically, from 28% to 45% of fatal episodes and even more for non-fatal episodes. Case fatality decline steadily, especially in younger ages.

Discussion 3Discussion 3

One possible explanation: the category ‘‘hanging, strangulation, and suffocation’’ includes sub-types of cases with different lethality and that the mixture of types has changed over time.

Other possible explanations: hospital admission practices have changed in a way that increases the proportion of such cases that are admitted (including less lethal types), or that under-ascertainment of fatal cases has increased.

Discussion 4Discussion 4

Poisoning by gases, the second most common method for fatal cases, showed a decline in lethality during the study period.

The emission controls have tended to decrease the toxicity of exhaust gas, which may have contributed to the observed decline in lethality.

Discussion 5Discussion 5

The ‘‘gender paradox’’ of suicide

The present study does not explain these differences, but prompts questions for future work.

Discussion 6Discussion 6

Case fatality generally increased with age, although with different patterns for each suicide method.

The decline with age of physiological robustness probably accounts for part of this effect .

Implications for preventionImplications for prevention

We should understand suicidality by considering non-fatal as well as fatal cases.

The demographic and temporal patterns can usefully inform planning for prevention and interpretation of trends in suicide.

Determinants of the pattern of methods used are poorly understood, limiting options for prevention.

ConclusionsConclusions

method-specific lethality by gender and age is so different.

Lethality of the suicide methods changes over time.

Understanding of suicidality in populations, on which prevention efforts depend, requires explanation of these findings.

Comments 1Comments 1

The study is a very good research that add the data to the literature of suicidal research .

We broaden the view from this paper.The advantages are addressed by the

author too many times, now I try to find the limitation of the paper.

Comments 2Comments 2

This research is a retrospective study ,so it has the common limitation of all this type study . It is very hard to do the quality control of the study.

Comments 3Comments 3

Suicidal problem is so complicated, but this study only choose a little variables such as age and gender.

For example, the economic status and the income will decide which self-harm means we choose.

Perhaps other variables will work on the results. But we never know according to this research.

Comments 4Comments 4

As the author says, because of lack of data, Suicidal acts that did not result in hospital admission or death were not included.

This may make the selection bias.

Comments 5Comments 5

It is just a descriptive study. We should design a prospective study

that with more variables, well quality control, multivariate analysis .

Comments 6Comments 6

Because of the different culture, we can not use the conclusion directly.

But I think that it is very important to build a national data base of the suicide in China.

Thank you