Lethality of suicide methods

1. Lethality of suicide methods Research Centre for Injury Studies, Flinders University, Adelaide, SA, Australia A A Elnour J Harrison

2. Outline Luo Xiaomin • Introduction • Methods • Results • Discussion • Comments Zhang Xia

3. Introduction • 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.

4. Introduction • 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.

5. Introduction • 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

6. Outline • Methods • Results • Discussion • Comments

7. Methods • 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)

8. Firearms Hanging, Strangulation and Suffocation (Hanging/Suffocation) Poisoning by gases and vapors (Gases/Vapors) Poisoning by and exposure to solid or liquid substances (Drugs/Poisons) Drowning and Submersion Jumping from a height Cutting and piercing by sharp objects (sharp objects) Lying or jumping before a moving object Crashing a motor vehicle Other and unspecified Methods Specified 10 types of method of self-harm in terms of ICD-9 and ICD-10.

9. Methods • 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.

11. Methods • 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.

12. Outline • Results • Discussion • Comments

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

14. Total episodes of intentional self-harm increased Non-fatal episodes increased Fatal episodes increased and then decreased

15. Method-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.

16. Figure 2 Method-specific case fatality by sex, Australia, 1 July 1993 to 30 June 2003. • For each suicidemethod, case fatality was higher in males.

17. Figure 3 Method-specific case fatality by age, Australia, 1 July 1993 to 30 June 2003. • For each suicide method, case fatality was higher in older age groups.

18. Figure 4 Method-specific time trends in case fatality, 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.

19. Outline • Discussion • Comments

20. Review 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.

21. Discussion---advantage • 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.

22. Discussion 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).

23. Discussion 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.

24. Discussion 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.

25. Discussion 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.

26. Discussion 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.

27. Discussion 5 • The ‘‘gender paradox’’ of suicide • The present study does not explain these differences, but prompts questions for future work.

28. Discussion 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 .

29. Implications 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.

30. Conclusions • 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.

31. Comments 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.

32. Comments 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.

33. Comments 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.

34. Comments 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.

35. Comments 5 • It is just a descriptive study. • We should design a prospective study that with more variables, well quality control, multivariate analysis .

36. Comments 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.

37. Thank you