Research A prospective cohort study of trends in self- poisoning, Newcastle, Australia, 1987–2012: plus ça change, plus c’est la même chose Despite ntentional poisoning is a major Abstract massive public health problem and gener- Objective: To examine inhospital mortality and morbidity associated with I ally occurs in the context of delib- self-poisoning with different drug classes over an extended period. increases in erate self-harm and drug misuse. Design, setting and participants: A prospective cohort study over 26 years the number of There are 60 International Statistical (1987–2012) with limited follow-up of patients presenting consecutively to a primary and tertiary referral toxicology centre covering Newcastle, Lake antidepressant Classification of Diseases and Related Health Problems, 10th revision (ICD- Macquarie and Port Stephens, Australia. prescriptions, 10) codes for drug-related deaths. In Main outcome measures: Hospital length of stay, types of drugs ingested, neither rates 2009, these codes together accounted intensive care unit (ICU) admission, requirement for ventilation, inhospital deaths and rates of antidepressant drug use in Australia. of self-harm for 6.4% of male and 5.5% of female total years of potential life lost in Results: Over the study period, there were 17 266 admissions of nor severity of Australia.1 Most deaths are in young patients poisoned by 34 342 substances (16 723 drugs available only on people, and drug-related deaths ac- prescription). The median length of stay was 16 hours, 12.2% of patients antidepressant (2101/17 266) were admitted to an ICU, 7.4% (1281/17 266) were ventilated count for a large proportion of lost poisoning and 78 (0.45%) died in hospital. Patient demographics, social and years of life — causing about 25% of psychiatric factors remained stable over the 26-year period, but case 1 increased completed suicides. The estimated fatality decreased (from 0.77% [15/1955] to 0.17% [7/4060]) as did ICU markedly Australian rate of people hospitalised admissions (19.2% [376/1955] to 6.9% [280/4060]), ventilation (13.7% for self-poisoning of 119 per 100 000 [268/1955] to 4.8% [193/4060]) and LOS. The most frequently ingested population per year2 substantially substances were alcohol, benzodiazepines, paracetamol, antidepressants underestimates total numbers as and antipsychotics. There was a substantial fall in some highly toxic drugs many patients are not admitted or (tricyclic antidepressants, barbiturates, conventional antipsychotics and do not present.3 Most poisonings are theophylline), but increases in less toxic selective serotonin reuptake inhibitors, serotonin–noradrenaline reuptake inhibitors and paracetamol. in young adults and are impulsive A greater than sixfold increase in community antidepressant use was or unplanned. Morbidity and mor- accompanied by only minor changes in overall and antidepressant self- tality from poisoning has proved poisoning rates. surprisingly responsive to targeted Conclusion: Over two decades, there were decreases in poisonings by public health interventions to reduce many highly toxic drugs which were associated with substantial reductions the availability of means to poison in morbidity and inhospital deaths. Despite massive increases in the oneself accidently or deliberately.4,5 number of antidepressant prescriptions, neither rates of self-harm nor the Identification of drugs causing dis- proportion of antidepressant poisonings increased markedly. proportionate numbers of poison- Nicholas A Buckley ings, morbidity or deaths is thus a BMed, FRACP, MD1 key aspect of an effective toxicovigi- and antidepressant self-poisoning, 24 hours/day toxicology treatment Ian M Whyte lance system. and examined changes in prescrib- MB BS(Hons), FRACP, service for a population of about 2,3 FACMT We aimed to examine inhospital mor- ing of and self-poisoning with sev- 500 000. From 1992, ambulances di- eral drugs that have previously been Andrew H Dawson bidity and mortality associated with verted all poisoning presentations 4 MB BS, FRCP, FRACP poisoning in the greater Newcastle identified as having higher relative in the lower Hunter to this service. toxicity in overdose: short-acting bar- Geoffrey K Isbister region over 26 years and to broadly HATS currently has direct clinical 2,3 BSc, FACEM, MD determine what factors have (and biturates, dextropropoxyphene, chlo- responsibility for all poisoned adult ral hydrate, dothiepin, thioridazine, have not) changed over this time, patients in all hospitals in the greater 1 University of Sydney, pheniramine, temazepam, amisul- Sydney, NSW. during which there have been sub- Newcastle region and provides a ter- 2 Calvary Mater Newcastle, pride, alprazolam, venlafaxine and tiary referral service to Maitland and stantial changes in medication use. 10-15 Newcastle, NSW. citalopram. the Hunter Valley. HATS routinely 3 University of Newcastle, In particular, the use of psychotropic Newcastle, NSW. drugs has changed and there have records data on patients who present 4 Royal Prince Alfred Hospital, been large increases in antidepres- to hospital (even if the poisoning is Sydney, NSW. Methods sant prescribing in Australia over uncomplicated).16 Previous studies geoff.isbister@ 6,7 on poisoning in Newcastle17,18 have gmail.com the past three decades. Favourable This is a cohort study of patients pre- and unfavourable effects on popula- senting consecutively after self-poi- shown that no patients were treated tion suicide rates have been postu- soning to the Hunter Area Toxicology exclusively in private hospitals or by doi: 10.5694/mja14.01116 lated for antidepressants.8,9 Thus we Service (HATS) between January their family doctor, indicating that assessed the effect of the increase in 1987 and December 2012. Since 1987, most presentations to medical care Online first 27/04/15 antidepressant prescribing on total HATS has provided a comprehensive facilities are recorded. This cohort 438 MJA 202 (8) · 4 May 2015 Research does not comprehensively cover increased over the first 8 years, but 1 Morbidity and mortality due to self- unintentional childhood (age < 14 since 1995 has been quite stable poisoning, 1987–2012, measured by need years) poisonings. The local human (HATS became well established in for intensive care and ventilation, length research ethics committee has previ- 1994) (Appendix 1). of stay and fatality* ously granted an exemption regard- Of the total admissions, 15 327 (88.8%) Admitted to intensive care unit ing use of the database and patient were attempts at self-harm and the Ventilated information for research. remainder were a mixture of unin- A structured data collection form tentional, iatrogenic and recreational 20% is used by HATS to prospectively self-poisonings. (Data are generally 15% capture information on patient presented for admissions, and may demographics (age, sex, postcode), thus include the same patient with 10% drugs ingested (including doses), different poisonings.) The median co-ingested substances, regular age of admitted patients was 32 5% medications and management and years (range, 14–97 years) and the complications of poisoning.19 At dis- female : male ratio was 1.6 : 1 (10 514 Proportion of admissions 0 charge, further information is col- female, 6711 male and 39 transgender lected (eg, hospital length of stay patient admissions). The median LOS 20 [LOS], psychiatric and substance was 16 hours (interquartile range, misuse diagnoses). Data are rou- 9.3–25.7 hours; total time spent in 15 tinely entered into a fully relational hospital, 15 688 hours). Of the total Microsoft Access database separate admissions, 2101 involved admission 10 (hours) to the hospital’s main medical record of the patient to an intensive care unit Length of stay у 5 system. Data on all patients aged 14 (ICU) (12.2%) and 1281 involved ven- Median length of stay years who presented following self- tilation of the patient (7.4%). There 0 poisoning were analysed. were 78 inpatient deaths (0.45% of admissions). 1.0% Analyses of population-referenced Fatality data (ie, rates) were restricted to We investigated the changes in mor- 0.8% postcodes that predominantly cover bidity and mortality over the study Newcastle, Lake Macquarie and Port period by dividing admissions into 0.6% Stephens. Changes in total self-poi- those in the first 6 years, reported 0.4% soning rates in the four statistical sub- previously,20 and four subsequent divisions in this area were examined 5-year periods (Box 1). Over this died in hospital 0.2% between 1991 and 2011. Changes in period, the rate of admission to ICU 0 rates of self-poisoning using the main dropped from 19.2% (376/1955) to Proportion of patients who antidepressant drug classes (tricy- 6.9% (280/4060) and rate of mechani- clic antidepressants [TCAs], selective cal ventilation from 13.7% (268/1955) 1987–19921993–1997 serotonin reuptake inhibitors [SSRIs], to 4.8% (193/4060). The fatality rate 1998–20022003–20072008–2012 serotonin–noradrenaline reuptake dropped from 0.77% (15/1955) to inhibitors [SNRIs], monoamine oxi- 0.17% (7/4060). The median LOS * Data were divided into five periods with roughly equal patient numbers. dase inhibitors [MAOIs] and other) decreased from 20.5 hours in the were also examined. Data on rates of first 6 years to about 16 hours in all antidepressant drug use in these drug subsequent 5-year periods. 7.7%), d ivorce d (1302, 7.5%), w idowe d classes (standardised by the defined In the 17 266 admissions, a previous (409, 2.4%), in de facto relationships daily dose [DDD]) in Australia history of psychiatric illness (9692, (79, 0.5%), other (13, 0.1%); and data from 1991 to 2011 were taken from 56.1%), previous admission for a psy- were missing for the remainder (467, Australian government publications. chiatric episode (6426, 37.2%), previ- 2.7%). These demographic, social and We have previously shown that these ous suicide attempt (9665, 56.0%) psychiatric factors remained stable, data agreed within two significant and history of alcohol or drug mis- except for a slight rise in the propor- digits with Newcastle-specific data use (8466, 49.0%) were commonly tion of patients reporting previous for a range of medications.11 recorded.