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Deliberate self-harm patients in the emergency department: factors associated with repeated self-harm among 1524 patients
  1. Katarina Bilén1,
  2. Carin Ottosson3,
  3. Maaret Castrén2,
  4. Sari Ponzer3,
  5. Carina Ursing1,
  6. Pentti Ranta4,
  7. Karin Ekdahl4,
  8. Hans Pettersson5
  1. 1Department of Clinical Science and Education, Section of Internal medicine, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
  2. 2Department of Clinical Science and Education, Section of Emergency Medicine, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
  3. 3Department of Clinical Science and Education, Section of Orthopaedic Surgery, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
  4. 4Department of Clinical Science and Education, Section of Psychiatry, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
  5. 5Department of Clinical Science and Education, Section of Biostatistics, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
  1. Correspondence to Katarina Bilén, Department of Internal Medicine, Södersjukhuset, S–118 83 Stockholm, Sweden; katarina.bilen{at}sodersjukhuset.se

Abstract

Objectives (1) investigate risk factors associated with repeated deliberate self-harm (DSH) among patients attending the emergency department due to DSH, (2) stratify these patients into risk categories for repeated DSH and (3) estimate the proportion of repeated DSH within 12 months.

Design A consecutive series of individuals who attended one of Scandinavia's largest emergency departments during 2003–2005 due to DSH. Data on sociodemographic factors, diagnoses and treatment, previous DSH at any healthcare facility in Sweden (2002–2005) and circumstances of the index DSH episode were collected from hospital charts and national databases. A nationwide register based on follow-ups of any new DSH or death by suicide during 2003–2006.

Main outcome measure Repeated DSH episode or suicide.

Results 1524 patients were included. The cumulative incidence for patients repeating DSH within 12 months after the index episode was 26.8% (95% CI: 24.6 to 29.0). Risk factors associated with repeating DSH included previous DSH, female gender, self-injury as a method for DSH and if the self-injury required a surgical procedure, current psychiatric or antidepressant treatment and if the patient suffered from a substance use disorder or adult personality disorder or did not have children under the age of six.

Conclusion Patients attending an emergency department due to DSH have a high risk of repeating their self-harm behaviour. We present a model for risk stratification for repeated DSH describing low-risk (18%), median-risk (28% to 32%) and high-risk (47% to 72%). Our results might help caretakers to direct optimal resources to these groups.

  • Deliberate self-harm
  • self-injury
  • self-poisoning
  • risk factors
  • emergency service
  • acute medicine-other
  • mental health
  • self harm
  • trauma
  • epidemiology

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Introduction

Patients who harm themselves are quite often seen by clinical staff working in an emergency department (ED). Although there is a considerable amount of literature on risk factors for deliberate self-harm (DSH) and repetition of DSH, only a few studies have used these risk factors to stratify patients according to risk for repeated DSH with the goal of providing guidance for ED clinical staff in the acute assessment of these patients.1–3

Deliberate self-harm (DSH) is the term used to describe an act of non-fatal, self-inflicted harm and includes all methods of self-harm.4 DSH is defined as any act by an individual with the intent of harming him or herself physically and which may result in some harm. The patients' motivations for DSH vary and are often difficult to investigate.5–7

DSH can be regarded as a major public health problem that results in major suffering for the individual and large costs to society.8 DSH has been shown to be strongly associated with an increased risk of suicide: previous studies have shown that 20–25% of the people who die from suicide have had an episode of self-harm within the year before their death.9 10 It has also been demonstrated that the risk of suicide among DSH patients is much higher than in the general population and that they have an overall increased mortality due to a wide range of causes.11–13 The risk of subsequent suicide after DSH is highest within the first 6 months, but it has been shown to remain increased for a long period of time, perhaps even for a lifetime.10 14

Previous DSH is known to be a strong risk factor for repetition and repetition is common within the first year after an episode of DSH.3 15 However, few studies have reported repetition of DSH in a nationwide perspective and therefore little is known about whether DSH patients also have a tendency to seek healthcare outside their residential area. Other risk factors reported to be associated with repetition are psychiatric treatment, self-injury as a method for self-harm, alcohol and drug misuse, and unemployment.16 17

From the perspective of ED clinical staff not specialised in psychiatric care, it is beneficial to classify DSH patients according to risk for repetition already on their arrival in hospital in order to set the correct priorities for this patient group.

Our study is based on acute psychiatric assessments (ie, index episodes) at an ED, on health data registers and on official statistics kept by the Swedish government. Our aim was (1) to investigate the risk factors associated with repetition of self-harm or suicide in a consecutive series of patients in a DSH population at an ED, (2) to stratify this population according to risk for repeated DSH and (3) to determine the proportion of individuals who repeated deliberate acts of self-harm within 12 months with a nationwide follow-up.

Material and methods

Patients

This is a study based on an ED register complemented with a review of somatic and psychiatric patient records and with a nationwide follow-up via healthcare registers.

All patients over 18 years of age treated at a general hospital ED in a city area (Stockholm, Sweden) due to DSH (ie, deliberate self-harm including all self-harm methods, regardless of intent or medical seriousness), during the period from 1 January 2003 to 31 December 2005 were included. The index episode (ie, the inclusion of the patient in the study) was defined as the first DSH attendance that led to a psychiatric assessment during the period (2003–2005) or, if a psychiatric assessment was not performed, the first DSH attendance for an individual during these years.

All residents of Sweden are included in the National Registry under a unique personal identification number allocated at birth or on receiving a residence permit. Each visit to an ED, admission to hospital or open care contact is recorded with the patient's personal identification number, enabling automatic and accurate record linkages. The registers of Statistics Sweden and The National Board of Health and Welfare are also linked by the personal identification number.

Use of the International Classification of Diseases (ICD-10) by both somatic and psychiatric care units made it possible to identify DSH patients attending Södersjukhuset during 2003–2005, to identify previous DSH patients (2002–2005) and new DSH/suicide patients nationwide (2003–2006) using the ICD-10 codes X60-X84.

Baseline data

We used a structured protocol to collect data from the hospital charts (medical and psychiatric history and examination). The protocol included method of DSH, if the self-injury required a surgical procedure that is.general anaesthesia or admission for surgery, substance used for self-poisoning, current and previous psychiatric treatment, current antidepressant treatment, influence of alcohol at the time of self-harm (serum ethanol or whether it was clearly mentioned in hospital charts that the patient was under the influence of alcohol), precipitant events before self-harm, suicidal intention, discharge information and psychiatric diagnosis.

The manual data collection from the hospital charts was performed by the authors assisted by trained staff. The data on the index episode were systematically checked for accuracy by one of the authors (KB).

Data were collected from Statistics Sweden concerning such sociodemographic factors as age, gender, marital status, housing status, employment, educational level and early retirement pension. Data on previous DSH episodes registered at any healthcare unit in Sweden were collected from the National Board of Health and Welfare records.

Follow-up

Our main outcome was repeated DSH or death by suicide.

Statistical analyses

If data on the precipitants and circumstances of the index episode and on previous/current psychiatric treatment, previous abuse and antidepressant treatment were not reported in any of the hospital records (somatic or psychiatric), we were not able to investigate this further so that these factors were classified as ‘no’ in the statistical analysis (table 1).

Table 1

Factors associated with repeated deliberate self-harm (DSH) in 1524 patients attending the emergency department due to DSH

We used Cox proportional hazard models to evaluate the influence of different factors on the risk of repetition and to account for differences in the length of follow-up. Risk time (person-days) was accrued from the index episode of self-harm until the first repetition X60-X84 or suicide X60-X84 or censored at death from other causes or at the end of follow-up, whichever occurred first. No imputations were applied for missing data. Our model strategy was as follows: first, we studied the unadjusted association between repetition and each separate factor in univariable models. Second, a multivariable model was developed by including all factors that showed an unadjusted association (p value <0.05) with repetition. We report HRs with their corresponding 95% CIs. All variables were tested by the two-sided Wald χ2 test.

We used classification trees to stratify the patients into groups according to risk of repetition after DSH. We used the χ2 automatic interaction detection (CHAID) algorithm to build the tree.18 A CHAID analysis starts with all patients in one group. Each possible split on each factor in table 1 is considered to find the split that leads to the strongest association with the dependent variable: repetition of self-harm after an index episode of self-harm (yes/no). The resulting groups were split until one of the following stop criteria were reached: tree depth was limited to three levels, no group with less than 50 patients was formed and no split with a Bonferroni adjustment of less than 0.05 was executed.

We estimated the 1-year incidence of repetition of DSH by calculating the proportion (with the 95% CI based on the normal approximation) of individuals repeating within 365 days of the index episode of self-harm.

The statistical analysis was carried out using SPSS V.17 and V.18.

The study was approved by the Regional Ethics Committee at Karolinska Institutet, Sweden.

Results

Patient characteristics at the index episode

During the study period (2003–2005), a total of 1679 patients were identified with an episode of DSH. Criteria for exclusion were: death at the index episode (n=16); patient leaving the ED before a somatic and/or psychiatric assessment was made (n=8); hospital chart could not be found (n=41); incorrect classification in the register, that is, not a DSH according to the hospital chart (n=39); and personal identification number missing or inaccurate (n=51), leaving a total of 1524 patients in the study population.

Demographic data are displayed in table 1. The mean age was 39.5 years (range 18 to 92 years), 46% were under 35 years of age and 65% were female. Housing status indicated that 56% were single and 10% had young children (0−6 years of age). Only 18% had more than a 12-year educational level (in Sweden there are 9 years of compulsory schooling but 99% continue with a 3-year secondary education).

In all, 34% of patients were discharged home and 66% were admitted to hospital, with a mean period of acute hospitalisation of 2 days. A psychiatric assessment and psychiatric diagnosis was made in 94% of the patients by the hospital psychiatric consultant team.

The most common mental and behavioural disorders at the index episode were affective disorder (29%), adult personality disorder (26%), substance use disorder (18%) and neurotic disorder (18%). A single mental and behavioural disorder was diagnosed in 61% of all patients and 16% (251 patients) had two different mental and behavioural disorders, the most common combinations being adult personality disorder combined with substance use disorder in 23% (58 patients), and adult personality disorder combined with affective disorder in 23% (58 patients).

The most common method of DSH was self-poisoning (86%) and the most common drug used (single or mixed self-poisoning) was benzodiazepines (45%). Two different drugs were used by 20% (261 patients), benzodiazepines and propiomazin (phenothiazine drug) by 15% (38 patients) and benzodiazepines and antidepressants by 13% (35 patients) being the most common combinations. Self-injury as a method for self-harm was reported by 12% of all the patients and 2% used both self-injury and self-poisoning as the method of DSH.

Incidence of repetition of DSH

Within the first year after the index episode, 408 patients (26.8% (95% CI: 24.6 to 29.0)) repeated DSH and 75% of these repeated cases of DSH occurred within six months and 10.5% within the first 3 days after the index episode (figure 1).

Figure 1

Time to repeat DSH within the first year after the index episode (n=408).

In total, 484 of the 1524 patients (31.8% (95% CI: 29.4 to 34.1)) repeated DSH after the index episode within the period (2003–2006). Of the 484 who repeated DSH, 26% attended another hospital than at the index episode. Overall, the repeated DSH patients attended 31 different hospitals in Sweden during the period.

In total, 6% (96/1524) of the patients were deceased on 31 December 2006, including 35 patients (2.3%) who died by suicide according to ICD-10 (X60-X84). Of the patients who died by suicide, 63% were men and 46% were over the age of 45. Of the repeating patients, 4% (21/484) repeated by committing suicide.

Factors associated with repetition of DSH

The factors associated with repeated DSH in the adjusted analysis were: previous DSH; female gender; self-injury as the method for DSH and if the self-injury required a surgical procedure; if the patient was under current psychiatric or antidepressant treatment; if the patient suffered from a substance use disorder; any adult personality disorder; or did not have children under the age of 6 (table 1).

The stratification according to the classification tree analysis showed that the occurrence of repeated DSH or suicide for patients attending the ED due to DSH ranged between 18% and 72% within different groups (figure 2). The patients with the highest risk (47%–72%) of repetition had a previous episode of DSH and a current psychiatric contact. Alternatively, they had a previous episode of self-harm without a psychiatric contact but a suicidal intention (48%). Another group with a high risk of repetition (47%) were patients without a previous history of DSH with an adult personality diagnosis and a psychiatric contact. In contrast, the group with the lowest occurrence of repetition (18%), consisted of patients with no previous episode of DSH, no adult personality diagnosis and not taking antidepressant medication. In addition, there was a class of patients with a risk between 28% and 32% (figure 2).

Figure 2

Classification tree showing the factors which, at each step, had the strongest association with repeated DSH among patients attending the emergency department due to DSH (n=1524) within the whole study period (2003–2006). The percentage repeated DSH is counted on the total number of patients in each node. The χ2 automatic interaction detection (CHAID) algorithm was used to build the tree. All Bonferroni adjusted values were <0.05 for all nodes.

Discussion

Principal findings

First, our study showed that earlier known risk factors, such as previous DSH and female gender, are associated with repeated DSH, but also that self-injury requiring a surgical procedure, current antidepressant treatment, psychiatric diagnoses of substance use disorder and adult personality disorder and having no young children were also associated with repeated DSH and not only with DSH as reported previously.19 Second, our risk-stratification analysis indicated that within the group attending an ED due to DSH, there were patients with different risks of repetition (figure 2) and third, that patients who attend an ED due to DSH often repeated their self-destructive act within a short period of time and that they often attended another hospital.

Comparison with other studies, particularly considering any differences in results

Currently being on an antidepressant medication was found to be associated with repetition of DSH, which might indicate that these patients already had a poor mental health status and were therefore at a higher risk for repetition or that the antidepressant medications are not helpful in preventing DSH repetition. The association between having no young children and repetition might be explained by the fact that if a patient has young children and is treated due to DSH, other authorities might be involved and other caretakers are quickly alerted, which is probably not the case with patients without young children.

The association between self-injury requiring surgical treatment and repetition of DSH might indicate more severe DSH and that the suicidal intention was high, which should alert clinical staff and other caretakers to make sure that this group of patients is provided with adequate resources. In contrast to previous studies, unemployment was not associated with repetition of DSH in our study.1 3

Previous sexual abuse has also been shown to be associated with DSH and even though we found a higher risk of repeating DSH for these patients, we could not demonstrate a statistical significance.1 19 This might be due to the relatively small number of patients with previous sexual abuse in our population (4%).

All the factors used in the risk stratification, except age, were also significantly associated with a repeat DSH in the Cox regression, which takes the time to repetition into account. Two of the factors in our risk stratification (previous self-harm, current psychiatric treatment) have also been found to be related to risk for repeated DSH in another study.2 However, in contrast to our study, that study dealt with repetition within 6 months. We chose to study a longer period for repetition because the risk of suicide and death after DSH is known to remain for a long time, as well as the risk for repetition, even though the risk is highest during the first months after the DSH episode.

Previous DSH is a risk factor for suicide, which was also confirmed in our study, 4% of those who repeated committed suicide after the index period. This emphasises the importance of identifying individuals with a high risk of repeated DSH.

The incidence of repetition was higher in our population than in previous studies which might be explained by the fact that we were able to record repeated DSH occurring anywhere in Sweden and not only at the hospital where the index episode was treated or in the nearby region.3 11 20 This indicates that the occurrence of repetition might be underestimated in other studies.

Methodological considerations (strength and limitations)

An important strength of the present study was the comparatively large study population consisting of all patients attending the ED due to DSH during 3 years at a single comparatively large hospital serving approximately 600 000 inhabitants or one-fifteenth of the Swedish population. In this study, 34% of the patients were discharged from the ED and would not have been recognised if only patients admitted to inpatient care were included. This ensured representativity of the study population and provided opportunities to assess the association between different risk factors and repeated DSH with reasonable statistical precision.

One limitation of this study is that the patients were not prospectively assessed according to a study protocol. All information was obtained retrospectively from medical and psychiatric hospital records. Some doctors wrote elaborate records while others were rather brief. We tried to minimise the impact of inhomogeneous information by applying a strict protocol when extracting data from the medical and psychiatric records in order to achieve high data reliability.

We believe that omission of information played a more important role than incorrect information. If, for example, a psychiatric record stated that a patient had been sexually abused, he or she probably had been abused. If nothing about sexual abuse was found in the psychiatric records, the patient still might have been abused. It is therefore likely that we have underestimated the occurrence of risk factors based on information extracted from the medical and psychiatric records. This limitation does not, however, affect the information about repeated DSH, which is complete and based on data from national registers.

It is also a weakness that the stratification has not been validated in another study population. Thus, our stratification probably has good internal validity, but the external validity is unknown and needs to be evaluated in future studies.

Clinical implications

Patients who harm themselves are seen quite often in EDs. It is important for all healthcare personnel, and especially for ED physicians, to better understand how these patients should be assessed and treated. The risk of repetition is high among some of these patients while it is low among others in the rather heterogeneous group of patients seeking acute somatic care due to DSH. Our stratification implies that in order to identify patients with the highest risk (47%–72%) of DSH repetition (figure 1), clinical staff should take special note of patients with a previous DSH episode who have a psychiatric contact or those without a psychiatric contact but with suicidal intention. Furthermore, among patients without previous DSH, those with an adult personality diagnosis and a psychiatric contact are at high risk.

Conclusions

Our findings might make it easier to identify risk patients for repetition of DSH already in the ED so that resources can be provided for this group of patients. There is a need for further prospective studies in which tools, based on risk factors for repetition, can be developed to identify patients at risk for repetition of DSH. If this group of patients can be identified and offered the right resources, it might present an opportunity to prevent repetition of DSH and suicide.

References

View Abstract

Footnotes

  • Funding This study was supported by Research Fund of Stockholm County Council, Karolinska Institutet (KID funding) and Capios forskningsstiftelse.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the Regional Ethics committee at Karolinska Institutet, Sweden.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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