Repetition of deliberate self-poisoning in rural Sri Lanka

Repetition of deliberate self harm is an important predictor of subsequent suicide. Repetition rates in Asian countries appear to be significantly lower than in western high income countries. The reason for these reported differences is not clear and has been suggested to due methodological differences or the impact of access to more lethal means of self harm. This prospective study determines the rates and demographic pattern of deliberate self-poisoning, suicide and fatal and non fatal repeated deliberate self-poisoning in rural Sri Lanka. Details of deliberate self poisoning admission in all hospitals (n=46) and suicides reported to all the police stations (n=28) of a rural district were collected for 3 years, 2011-2013. Demographic details of the cohort of deliberate self-poisoning patients admitted to all hospitals in 2011 (N=4022), were screened to link with patient records and police reports of successive two years with high sensitivity using a computer program and manual matching was performed with higher specificity. Life time repetition was assessed in a randomly selected subset of DSP patients (n=438). There were 15,914 DSP admissions and 1078 suicides during the study period. Within the study area the deliberate self poisoning and suicide population incidences were, 248.3/100,000 and 20.7/100,000 in 2012. Repetition rate for four weeks, one-year and two-years were 1.9% (95% CI 1.5-2.3%), 5.7% (95% CI 5.0 to 6.4) and 7.9% (95% CI 7.1 to 8.8) respectively. The median interval between two attempts were 92 (IQR 10 - 238) and 191 (IQR 29 - 419.5) days for the one and two-year repetition groups. The majority of patients used the same poison in the repeat attempt. Age and hospital stay of individuals with repetitive events were not significantly different from those who had no repetitive events. The two-year rate for suicide following DSP was 0.7% (95% CI 0.4-0.9%). Reported life time history of deliberate self harm attempts was 9.5% (95% CI 6.7-12.2%). The low comparative repetition rates in rural Sri Lanka was not explained by higher rates of suicide or access to more lethal means or differences in methodology.


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Deliberate self harm (DSH) is a major global public health problem. The World Health Organization 28 (WHO) projects the worldwide yearly suicide mortality rate will increase to 1.53 million and it will be 29 constitute 2.4 % of the total disease burden by 2020.
(1). While there is significant variation of suicide 30 rates between countries Sri Lanka's suicide rates have remained amongst the highest in the world, (2, 31 3).

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A recent meta-analysis estimated that one in 25 patients presenting to hospital for self-harm will 33 suicide in the next 5 years. (4).Understanding factors that influence the rate and pattern of repetition 34 of self harm has the potential to inform prevention strategies and optimal follow-up after a self-harm 35 episode. There appears to be geographic differences in the 1 year non-fatal repetition rates. In

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European studies 1 year non-fatal repetition rates was estimated as 17.1% (95% CI 15.9-18.4) while it 37 was lower in Asia (10.0%, 95% CI 7.3-13.6). (4). Possible proffered reasons for this included 38 methodological weakness of the Asian studies, higher lethality of self-poisoning and longer hospital 39 stay(4). It was suggested that identifying the reasons for this variation could provide insights into 40 optimal configuration of health care services (4). 159 The pattern of type of poison used for the repetitive events was similar to the pattern of the cohort.

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60% of individuals who ingested agro-chemicals used the same method for the next consecutive 161 event. Nearly half (47%) and more than half (55%) of individuals who overdosed medicines and 162 ingested oleander seeds used the same method for the next consecutive event. A majority, 24 163 (85.7%), of fatal repetitions were due to poisoning; two due to oleander and 22 agro-chemicals. One 165 individuals who ingested agro-chemicals at the fatal repetitive event used the same method at the 166 index event.

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The median hospital stay of DSP patients managed at peripheral hospitals, for both who had and did 170 not have repetitive attempts, were two days (   The risk of repetition is higher in initial post event period. The median times to repetition within 1 year 296 and 2 years were, 92 (IQR 10 -238) and 191 (IQR 29 -419.5) days respectively. The risk for repetition 297 is highest in the first 3 to 6 months after a suicide attempt, but remained substantially elevated from 298 the general population for at least 2 years (Bridge et al., 2006;Goldston et al., 1999;Lewinsohn, 299 Rohde, & Seeley, 1996). The median time to repetition within 1 year was 105 days in Taiwan (Kwok,   300 Yip, Gunnell, Kuo, & Chen, 2014   5.0 (4.0 to 5.9) 5.7 (5.0 to 6.4) 8.8 (7.6 to 10.1) 7.0 (5.9 to 8.2) 7.9 (7.1 to 8.8) 498 Table 2: four weeks, one year and two year repetition rates by age and sex