Examples of available data

Between 1979 and 1999, the standardised death rate from drugs other than alcohol and tobacco increased by 79%, from five to nine deaths per 100,000 persons, driven primarily by increases in deaths of males from opiates. Source: Australian Bureau of Statistics 2001, Australian Social Trends, 2001,Cat. no. 4102.0, ABS, Canberra. In 1998, opiate dependence, abuse or poisoning accounted for 52% of male and 42% of female hospital episodes attributable to the use of illicit drugs. Source: Ridolfo, B. and Stevenson, C. 2001, The quantification of drug-caused mortality and morbidity in Australia, 1998, Australian Institute of Health and Welfare, Canberra. In 2000, approximately 53% of people with a history of injecting drug use who were seen at needle and syringe programs, tested positive to hepatitis C. Source: National Centre in HIV Epidemiology and Clinical Research 2001, HIV/AIDS, viral hepatitis & sexually transmissible infections in Australia Annual Surveillance Report 2001, NCHECR, University of New South Wales, Sydney. In 1997, 4.9% of Australians aged 18 to 34 years had a drug use disorder. Source: Hall, W., Teesson, M., Lynskey, M. & Degenhardt, L. 1998, The Prevalence in the Past Year of Substance Use and ICD-10 Substance Use Disorders in Australian Adults: Findings from the National Survey of Mental Health and Well-being, NDARC Technical Report No. 63, National Drug and Alcohol Research Centre, University of New South Wales, Sydney.

3.1 Introduction

Illicit drug use is associated with a range of adverse effects on both physical and mental health. These may result from the immediate pharmacological action of the substance (e.g. overdose and other adverse effects), long term impact (e.g.consequential mental and behavioural disorders) and/or the lifestyle associated with obtaining and using an illicit substance (e.g. blood-borne viral infections, exposure to violence). Some of these health issues are directly and obviously related to illicit drug use. However, in other areas which may impact directly on health, the role of illicit drugs is not as obvious (e.g. inadequate diet).

Information on the health outcomes of illicit drug use comes mainly from the records of health service providers (such as hospitals and doctors), public health administration records (e.g. notifications of infectious diseases) and registrations of deaths. However, medical intervention does not occur for many relatively minor mental and physical conditions resulting from illicit drug use, nor for some episodes of serious conditions such as non-fatal overdoses. Consequently, the use of administrative data sources will under-estimate the occurrence of some health conditions. Further, administrative records provide little information on the poor lifestyle behaviours often associated with long-term illicit drug use.

Surveys can be used to assess the prevalence and social impact of these non-recorded conditions. For example, personal interviews can give information on the habits of injecting drug users which may contribute to their risk of contracting infectious diseases, or the extent of overdose experiences which occur without medical intervention.

This chapter outlines the main sources of national data regarding health outcomes from illicit drug use, categorised into deaths, health services, injecting drug users and other sources. Data issues relating to the identified sources are subsequently discussed, followed by a listing of identified gaps in available data.

Further details of each primary dataset are listed in Appendix 1, including the data items available and contact details. Data quality issues discussed in Chapter 7, for both administrative or survey data, are relevant to these sources.


3.2 Data sources

3.2.1 Deaths

Causes of Death collection (Appendix 1, A1.5) and National Mortality Database (Appendix 1, A1.21)

The major source of information on drug-related deaths is the Causes of Death collection maintained by the Australian Bureau of Statistics (ABS). The ABS collates and processes death information from all State and Territory Registrars of Births, Deaths and Marriages. National data are available in hardcopy from 1907 and electronically from 1968. Each year the Australian Institute of Health and Welfare (AIHW) obtains the ABS-processed deaths data from the Registrars and adds these records to their National Mortality Database, which contains time series data from 1964.

Information from each 'Medical Certificate of Cause of Death' is coded by the ABS according to the International Classification of Diseases (ICD). The ABS applies ICD rules for determining the underlying cause of death from the conditions and/or injury information provided on the death certificate and relevant information obtained from the coroner's office. The primary purpose of mortality coding is to identify the underlying cause of death. This is defined as the condition, disease or injury which initiated the train of events leading directly to death.

Deaths resulting from drug use may be classified to a number of categories and each drug of interest may not have a unique code (e.g. amphetamines and ecstasy have the same code). Hence, not all illicit drugs can be distinguished. The 10th revision of the ICD, used to code deaths since 1999, provides more detailed information regarding particular drugs (e.g. suicides by opiates) than did the previous editions of ICD. Limitations in the capability of ICD to classify deaths attributable to the use of a particular drug are outlined in 3.3 Data issues. Further details on the ICD codes involved in drug-related deaths are provided in Appendix 3.

In the case of an accidental or violent death, the underlying cause of death would be coded to the event (e.g. a car accident) rather than to the injury itself. In recognition of the need for additional information, since 1994 the ABS has flagged all records in which alcohol, tobacco or other drugs were mentioned on the death certificate or coroner's report. This drug flag indicates the presence of a drug, although it may not have contributed directly to the death (e.g. testing of a traffic accident victim indicated the recent use of amphetamines, although not in toxic quantities). Analysis of records with the drug flag gives some indication of the influence of alcohol, tobacco or other drugs on fatalities, but does not allow for any further distinction between types of drugs.

Commencing with deaths registered in 1997, the ABS now codes not only the underlying cause of death but also all associated causes mentioned on the death certificate. Where more than one drug is mentioned on the death certificate or coroner’s report, a poisoning code for each drug is now added to the record. This more extensive dataset will allow a more comprehensive and insightful study of mortality patterns, including those related to the use of drugs.

As well as date of death and cause of death, demographic data such as age, sex, birthplace, marital status and region of usual residence are recorded in these datasets. They can be used to analyse time series and geographic trends in drug-related deaths.

Detailed data concerning illicit drugs from these collections can be purchased from both the ABS and AIHW. Using data from the Causes of Death collection, the article ‘Drug-related deaths’ in the ABS publication Australian Social Trends, 2001 (Cat. no. 4102.0) is an example of the analysis which is possible using mortality data. Australian Drug Trends 2000: Findings from the Illicit Drug Reporting System (IDRS), (Topp et al., 2001) gives the number of deaths from opioids in each State between 1990 and 1999.

Mortality data and aetiological fractions (see 3.3 Data issues) have been used to calculate the number of deaths attributable to illicit drug use in 1998. The AIHW published this information in the report by Ridolfo and Stevenson (2001), The quantification of drug-caused mortality and morbidity in Australia, 1998 (Appendix 2, A2.9) This publication also contains data on the potential years of life lost as a result of drug-related deaths, a form of analysis which is very pertinent to illicit drug use because of the concentration of deaths in younger adult age groups.

National Coroners Information System (NCIS) (Appendix 1, A1.15)

The Monash University National Centre for Coronial Information (MUNCCI) has established a national database of those deaths which are referred to the Coroner's office of each State and Territory. These are deaths of a sudden or suspicious nature. Information from this centralised database, called the National Coroners Information System (NCIS), is now available for all States and Territories except Queensland, with plans for Queensland’s inclusion within a few years. The NCIS contains information pertaining to the death. This includes a narrative of events obtained from police reports to coroners, reports from the autopsy and forensic medical investigations (e.g., toxicology) as well as the coroner’s findings.

MUNCCI is currently coordinating a project aimed at developing standardised data items and procedures to be used across all States and Territories for drug-related deaths. To be implemented in late 2001, the NCIS Drugs Module Project will provide for a number of enhancements to the collection of information about deaths involving drugs. It will include a detailed classification of all drugs, from which specific classes of drugs can be separately identified. This project has been funded by the Commonwealth Department of Health and Aged Care (DHAC).

The NCIS database provides valuable information on drug-related deaths, including illicit drugs. While the public does not have access to this information, it is available for research by those involved in public health and safety. Researchers are required to obtain approval from various ethics committees.

3.2.2 General health services

Those experiencing health problems related to their use of illicit drugs use the general health services available in the community, such as doctors, hospitals and ambulances. Data on health problems associated with illicit drug use can only be obtained from those providers whose information systems separately identify these drug-related health problems. Even in these cases, information regarding the overall health condition of those who use illicit drugs usually cannot be extracted from these administrative systems, rather only information about health problems which result directly from the use of illicit drugs.

National Hospital Morbidity Database (Appendix 1, A1.19)

The AIHW annually collates information from each of the States and Territories concerning patients in all hospitals, both private and public, for their National Hospital Morbidity Database. Data are available from 1993-94.

This database can provide data on patients whose hospitalisation was related to drug use. Available data include demographic and geographic characteristics, principal and additional diagnoses, medical procedures and length of stay in hospital. Estimates of the hospitalisation costs are also available.

The diagnoses of ill-health, including poisoning by drugs, are classified using the International Classification of Diseases (ICD). This classification cannot distinguish the use of illicit drugs from the use of similar pharmaceutical drugs. It also groups some drug types together, limiting the detail available on individual drug types. These limitations are further discussed in 3.3 Data issues. Details concerning the structure of ICD are provided in Appendix 3.

Data from the National Hospital Morbidity Database on hospitalisation resulting from drug use are available for a fee from the AIHW. An analysis of data concerning hospitalisations for alcohol and drug related health conditions among hospital patients in 1997-98 is provided in the AIHW publication Alcohol and other drug treatment services: Development of a National Minimum Data Set (Grant & Petrie, 2001). Data are included indicating the co-morbidity of drug dependency and other mental illness.

The number of hospital separations attributable to illicit drug use in 1997-98 have been estimated using the hospital morbidity data and aetiological fractions (see 3.3 Data issues). These estimates are published in The quantification of drug-caused mortality and morbidity in Australia, 1998 (Ridolfo & Stevenson, 2001) (Appendix 2, A2.9).

Bettering the Evaluation and Care of Health (BEACH) (Appendix 1, A1.4)

Doctors in general practice deal with a wide range of health problems, including some connected to their patients' use of illicit drugs. Bettering the Evaluation and Care of Health (BEACH) is a national survey of the clinical activities of doctors in general practice and has been conducted annually since 1998 by the General Practice Statistics and Classification Unit, a collaborating unit of the AIHW and the University of Sydney. It records details of 100 consecutive doctor-patient encounters for each randomly selected doctor. Among the problems managed by the doctors in this survey are those classified as a ‘drug abuse’ problem, and this category can be further broken down according to drug type. The classification used is the International Classification of Primary Care, 2nd Edition (ICPC-2).

The AIHW has produced a report on each of the first two completed years of the continuous survey, the latest being General Practice Activity in Australia 1999-2000 by Britt et al. (2000). In the 1999-2000 survey, the occurrence of drug abuse problems was less than 1% of all 153,857 problems managed by the general practitioners surveyed, and no information on this issue was published. Nevertheless, data from the surveys relating to drug abuse problems are available from the General Practice Statistics and Classification Unit and the combination of data from two or three years of the survey should allow some useful analysis of the characteristics of drug-abuse patients and the treatments they receive.

Pharmaceutical Benefits Scheme

Information on the value and volume of claims paid by the Health Insurance Commission (HIC) to approved pharmacies for items listed in the Schedule of Pharmaceutical Benefits is available from the HIC website http://www.hic.gov.au. Items such as methadone and naloxone, which can be used for the treatment of opioid dependence and overdose, are included in this schedule. While data are available on the number of prescriptions completed for different drugs, the HIC cannot provide data on the number of people for whom those prescriptions are written, nor can it distinguish whether the drug is used for opioid dependence treatment or for other purposes such as analgesia.

3.2.3 Drug and alcohol treatment services

Drug and alcohol treatment services offer counselling and support to users who wish to change their drug/alcohol habits or avoid the adverse consequences of their use. A variety of treatment services offer diverse programs, approaches and sources of support. Methadone programs are one such specialised program of treatment, aimed specifically at those dependent on heroin.

The National Drug and Alcohol Research Centre (NDARC) is currently collecting and coordinating information from a number of different studies of treatments for opioid dependency. Called the National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD), this project aims to provide a means of comparison of the treatment trials which have recently been undertaken.

Clients of Treatment Service Agencies (COTSA) (Appendix 1, A1.6)

National surveys of Clients of Treatment Service Agencies (COTSA) were conducted by NDARC in 1990, 1992, 1995 and May 2001. All agencies which specialise in the treatment of people with drug and alcohol problems were asked to complete a survey form giving details about each client seen on a particular day.

Items collected include demographic details, the nature of the service provided and the type of drug problem. Information resulting from the 1995 survey is available in the publication by Torres et al., Clients of Treatment Service Agencies: March 1995 Census Findings. The detailed dataset is available on application from the Social Science Data Archives (Appendix 2, A2.5).

National Minimum Data Set for Alcohol and Other Drug Treatment Services (Appendix 1, A1.20)

Starting from the financial year 2000-01, publicly funded providers of drug and alcohol treatment services are required to supply a standardised set of summary data from their administrative systems to their State or Territory health authority. The AIHW will collate this information from each State or Territory annually. The resulting national data collection will provide information on the demographics and drug-use habits of those seeking help, as well as the number and types of treatment services available in different regions. Further details about the collection are available from the 2001 publication by Grant and Petrie Alcohol and other drug treatment services: Development of a National Minimum Data Set.

Methadone client statistics (Appendix 1, A1.13)

Outlets which supply methadone doses for the treatment of opioid dependency without also providing other treatment services (such as counselling or urine testing) are not required to report the data items specified in the National Minimum Data Set for Alcohol and Other Drug Treatment Services. However, clients on methadone programs are required to be registered with State and Territory health authorities to gain access to methadone, a pharmaceutical drug. The numbers of such registrations are provided annually to the DHAC.

Data on the number of methadone clients since 1986 are available from DHAC. Although they are not regularly published, these data can complement the information from the National Minimum Data Set. A time series of the number of clients of methadone-treatment services was included in the AIHW publication Statistics on drug use in Australia 1998 (Higgins, Cooper-Stanbury and Williams, 2000).

3.2.4 Injecting drug users

Extra health risks are associated with the injecting of illicit drugs, particularly the spread of blood-borne viruses such as hepatitis B, hepatitis C and HIV. These infectious diseases are spread by the unsafe practices often associated with injecting illicit drugs, such as non-sterile conditions and the sharing of needles and other equipment.

The transmission of infectious blood-borne viruses has public health implications as well as affecting individuals. A high prevalence of infection among injecting drug users provides a potential source of infection for the general population. Consequently, there has been considerable effort to minimise and monitor the prevalence of HIV among injecting drug users. Reducing the high rate of infection of hepatitis among injecting drug users has also become a major concern.

Injecting drug users are prominent in data from all of the sources mentioned above. In addition, there are a number of sources which focus specifically on injecting drug users, which are discussed below.

Australian Needle and Syringe Program (NSP) Survey (Appendix 1, A1.2)

Needle and syringe programs generally do not treat immediate health problems but rather aim to prevent the spread of blood-borne viruses by providing sterile injecting equipment and health information to those who inject drugs.

The Australian Needle and Syringe Program (NSP) Survey has been conducted annually since 1995. This survey, coordinated by the National Centre in HIV Epidemiology and Clinical Research (NCHECR), asks all clients attending selected needle and syringe program sites during a particular week to complete a short questionnaire and provide a finger-prick blood sample for HIV (Human Immunodeficiency Virus) and HCV (hepatitis C virus) antibody testing. Information from this survey includes demographic data, history of injecting drug use and risk behaviours, as well as the prevalence of HIV and HCV antibodies in the client population.

A time series of data is now available from this annual survey, as reported in the article by MacDonald et al. in the October 2001 issue of the Drug Trends Bulletin produced by NDARC. Summary results are available in HIV/AIDS, viral hepatitis & sexually transmissible infections in Australia Annual Surveillance Report 2001, edited by the NCHECR.

National AIDS Registry (Appendix 1, A1.14) and National HIV Database (Appendix 1, A1.17)

These two databases are maintained by the NCHECR. The information is provided by State and Territory health authorities, which require health practitioners to notify any diagnosis of HIV infection or AIDS. Data recorded on these databases include demographic details, date of diagnosis and source of exposure to the infection (such as the person’s reported history of receipt of blood, injecting drug use and type of sexual contact).

The NCHECR also produces a quarterly report of data from these public health notification systems, the Australian HIV Surveillance Report. A comprehensive source of relevant information available from these databases is the annual publication HIV/AIDS, viral hepatitis & sexually transmissible infections in Australia Annual Surveillance Report 2001, edited by the NCHECR. This annual publication presents data from many sources concerning the occurrence of HIV and related diseases in Australia. People who have injected drugs are one group of interest in regard to these infections.

Other surveys of injecting drug users

Questions on risk-taking behaviours and general health are included in the survey of injecting drug users conducted annually as part of the Illicit Drug Reporting System (IDRS) (Appendix 1, A1.10). This program also includes an annual survey of key informants who have regular contact with injecting drug users and who are asked questions about the health of injecting drug users. The IDRS, coordinated by NDARC, collects information in most capital cities in Australia and regularly disseminates results. Further details are available in 2.2.1 Major sources of data and Appendix 1, A1.10.

The Turning Point Alcohol and Drug Centre recently conducted a study in Sydney, Melbourne and Perth called the Australian Blood-borne virus Risk and Injecting Drug Use Study (ABRIDUS). Injecting drug users were asked questions specifically designed to obtain information about exact injecting practices which may relate to the transmission of hepatitis C, as distinct from the transmission of HIV. A final report is due to be published before the end of 2001. In addition, the Turning Point Alcohol and Drug Centre is currently conducting a study of the demand for new pharmaceutical therapies for opioid addiction, by surveying 1,000 users in Victoria, South Australia and New South Wales.

3.2.5 Other sources of data on health issues

National Survey of Mental Health and Wellbeing of Adults (SMHWB) (Appendix 1, A1.24)

This national household survey was conducted by the ABS in 1997, with approximately 10,600 people aged 18 years or over being interviewed. Diagnostic data in the survey were collected using a World Health Organization (WHO) endorsed instrument, the Composite International Diagnostic Interview (CIDI) schedule, to provide an estimate of the prevalence of major mental disorders in the Australian adult population.

The survey provides estimates of the number of people who meet the criteria for two drug related disorders: harmful use of drugs and dependence on drugs. As the survey also identifies other mental health problems and chronic physical conditions, results from the survey can indicate the extent of co-morbidity. Further information was collected on general wellbeing and disability. A range of sociodemographic items was included so that these data can be explored by age, sex, employment status, marital status, etc.

The National Survey of Mental Health and Wellbeing of Adults does not completely separate illicit drug use from the misuse of pharmaceutical drugs. Findings from this survey have been published in the ABS and NDARC publications listed in Appendix 1, A1.24. Further data are available for a fee from the ABS.

The National Drug Strategy Household Survey (NDSHS) (Appendix 1, A1.16)

The Commonwealth Government has funded a series of national household surveys on drug use, conducted every 2-3 years since 1985. These surveys approach a random selection of Australians aged 14 years or over. The most recent survey in this series is being conducted by AIHW during 2001, with results to be available in 2002.

As well as demographic information and details about behaviours in relation to drugs - illicit or otherwise - the 1998 survey asked questions concerning health problems people had experienced. Respondents were asked about their recent use of the services of a doctor or hospital, their rating of their general health and whether their physical or emotional wellbeing had interfered with what they would like to have done.

The AIHW report 1998 National Drug Strategy Household Survey: Detailed findings, by Adhikari and Summerill (2000), gives information from the 1998 survey. It is available on the AIHW website at http://www.aihw.gov.au.

Other surveys

Women’s Health Australia, previously known as the Australian Longitudinal Study of Women’s Health, commenced in 1995. It is a longitudinal study funded by DHAC and conducted by researchers from the University of Newcastle in collaboration with the University of Queensland. This study aims to follow six cohorts of Australian women over a number of years, gathering information on themes such as time use, health and use of health care services, experience of violence, life stages and key events. The cohort of women aged in their twenties was surveyed for illicit drug information for the first time in 2000. They were asked whether they had used specific drugs and whether they had injected illicit drugs. The results of these questions will be able to be cross-classified with a large range of information which was gained in the same survey and in previous and future surveys of the same women. Further information on the study is available on the website http://www.fec.newcastle.edu.au/wha.

Smaller surveys of specific groups of illicit drug users in various locations have been conducted by a variety of organisations. Although many of these studies are not primarily aimed at gathering health information, they can provide relevant information such as infectious diseases, overdoses and concurrent use of pharmaceutical drugs, for specific geographic areas. These surveys are outside the scope of this paper. Relevant datasets may be available from the Australian National University’s Social Science Data Archives (Appendix 2, A2.5). The results of specific studies may be reported in journals such as: the Australian Medical Journal; Addiction; Drug and Alcohol Review; and Drug and Alcohol Dependence. CD-ROM literature databases such as AustROM and AUSThealth can help to find relevant papers, and many are referenced in the publications listed in Appendix 2 Further references regarding illicit drug use .


3.3 Data issues

The discussion in Chapter 7 Data quality issues is very relevant to the datasets mentioned in this chapter. In addition, the following issues apply specifically to health-related data.

There is no simple measure of the health consequences of illicit drug use. The estimates produced by researchers will naturally depend on the purpose of the study, but may be compromised by the lack of comprehensive, coordinated data. As a result, large variations may occur in different studies in the numbers of deaths or cases of disease resulting from illicit drug use. The following factors influence the quality and relevance of statistical analyses undertaken in this complex area.

Definitions

The results of the various studies may be incomparable because they relate to a different population of users. Many of the data sources do not distinguish illicit drugs from pharmaceutical drugs and those using these data for secondary analysis make their own individual decisions as to which drugs they include in their study. The different sources also use a variety of definitions for terms such as ‘drug-related’ and ‘stimulants’, as discussed in Chapter 7 Data quality issues.

International Classification of Diseases (see also Appendix 3)

The capability of the morbidity and mortality datasets to produce reliable time series depends on a number of factors: the extent to which the classification system used to code illness and causes of death is capable of identifying drug-related conditions and deaths; the introduction of revisions of the classification system; and variation in the information provided on death certificates and hospital records over the decades as medical knowledge of, and community interest in, drug use has changed.

The most commonly used health classification in Australia is the International Classification of Diseases (ICD). As a statistical classification, it is designed to encompass the entire range of morbid conditions within a manageable number of categories. The periodic revisions of the ICD have been coordinated by the WHO since the sixth revision in 1948, when the original focus on causes of death was expanded to include non-fatal diseases.

For mortality data, ICD-9 (International Classification of Diseases, 9th revision) was used to code deaths from 1979 to 1998. For deaths registered from 1999 onwards, the 10th revision of this classification, ICD-10, is being used. As this change resulted in a significant break in time-series data, causes of all deaths registered in 1997 and 1998 have been coded in both ICD-9 and ICD-10.

Up to and including 1997-98, hospital data on illness had been coded to the modified version of ICD-9 known as ICD-9-CM (Clinical Modification). From July 1998, data on illness in the National Hospital Morbidity Database has been coded to an Australian modification of ICD-10, known as ICD-10-AM (Australian Modification).

Use of the ICD classification for morbidity and mortality coding presents some problems in identifying the impact of illicit drugs on illness and death. The structure of the classification is not conducive to identifying death and illness attributable to the use of a particular drug. Rather, a death or illness resulting from drug use may be primarily classified to either a medical condition (dependence, non-dependent abuse, psychoses), or an external cause (assault by poisoning, accidental poisoning, suicide by poisoning, undetermined). Within these categories, there is not always a unique code for each drug of interest and there is no provision to distinguish illicit drugs from others. However, ICD-10 provides for finer detail than earlier revisions, through the use of poisoning codes.

The complexity of classifying diseases and deaths related to drug use may result in a range of figures being quoted as the health consequences of drug use. It has also meant that the standard outputs from the morbidity and mortality collections do not contain figures on drug-related deaths. Appendix 3 has been included as a guide to the ICD classification regarding deaths resulting from the use of illicit drugs.

Measuring the health burden of illicit drug use

Basic measures of the prevalence of death and illness resulting from illicit drug use can be obtained from the relevant data within the Causes of Death collection, National Mortality Database and National Hospital Morbidity Database. An additional concern regarding the health consequences of illicit drug use is measuring the joint impact of the premature loss of life, ill-health and disability, particularly as the use of illicit drugs is concentrated among younger adults.

This requires input from other studies into associations between illicit drug use and health related conditions, as the use of illicit drugs is not only a direct cause of death and illness (e.g. heroin overdose), but is also a risk factor in other conditions (e.g. hepatitis). The attributable proportion, also known as the attributable risk or aetiological fraction, indicates the proportion of a health condition which could be attributed to a particular risk factor, such as the use of an illicit drug.

The method of obtaining aetiological fractions for illicit drugs, and the resultant fractions which apply to Australian data, are detailed in the 2001 publication The quantification of drug-caused mortality and morbidity in Australia, 1998, by Ridolfo and Stevenson (Appendix 2, A2.9) and the 1995 work by English et al. The more recent of these two publications gives estimates of the number of deaths and years of potential life lost (in 1998) attributable to illicit drug use as well as the number of hospital separations and patient days (in 1997-98), which are attributable to illicit drug use.

As the results of such analysis depend heavily on the quality of input data available, these figures could represent an underestimate of the health consequences of illicit drug use. If no studies show a causal relationship between use of an illicit drug and a health condition, an aetiological fraction for drug use cannot be calculated for that condition, although future studies may show such a relationship. Another factor to be considered is that the aetiological fractions are based on the prevalence of illicit drug use as obtained from the 1998 National Drug Strategy Household Survey, generally considered to be a conservative estimate of the actual extent of illicit drug use. This is due to the problems inherent in self-report responses to household surveys, as discussed in Chapter 7 Data quality issues.


3.4 Data gaps

Accidents

There is anecdotal evidence of a higher risk of injury from road accidents, machinery operation, falls and drownings while a person is under the influence of illicit drugs, but little data are available. There is increasing interest in information on this issue as some companies, looking at the implications for work-place safety and accident compensation, are implementing drug testing of employees. This issue of illicit drug use and work-place safety is more applicable to particular industry sectors, such as mining.

Drummer (1994) researched the records of drivers killed in road accidents in Victoria, New South Wales and Western Australia between 1990 and 1993. Although he found an increased culpability of drivers with drugs other than alcohol in their bloodstream, the increase was not statistically significant for the number of cases studied. Future inquiries into the association between accidental deaths and drug use will be assisted by the drugs module of the National Coroners Information System (Appendix 1, A1.15).

Emergency treatment

At present there is no national collection of data from hospital emergency wards and ambulance services in each State and Territory. Both of these health services are potential sources of information on accidents, overdose and acute psychotic episodes involving the use of illicit drugs. Information on the acute health consequences of illicit drug use, as well as the economic and social consequences of illicit drug use, would be more complete if data from these emergency medical interventions were available. As emergency treatment is usually provided in close proximity to the emergency site, these sources of data also have the potential to contribute to regional information regarding illicit drug use.

One of the problems in obtaining national data is the lack of uniformity in the types of detail maintained in the administrative records of these services. The Turning Point Alcohol and Drug Centre in Victoria is presently working on extending its system of monitoring ambulance attendances at non-fatal heroin overdoses in Melbourne, aiming to collate similar information from ambulance services across Australia.

Consequential health problems associated with illicit drug use

A cluster of health conditions associated with illicit drug use have been recognised, including substance abuse, addictions, depression, violence, suicide, schizophrenia and low birthweight of babies born to mothers who use illicit drugs. However, there are little data concerning such medium and long-term health consequences. The lack of Australian studies on illicit drug use in relation to illness or injury was noted by English et al. (1995), as a result of their extensive research into this aspect of illicit drug use.

Linking of medical records

Further analysis of hospital records would be possible if the records from different hospital episodes for the same patient could be linked. The Health Department of Western Australia has done some work on this, and an example of some results from this type of work can be seen in the 1999 report by Patterson et al., First-time hospital admissions with illicit drug problems in Indigenous and non-Indigenous Western Australians: an application of record linkage to public health surveillance. The AIHW is looking at such possibilities as part of the National Health Record Linkage Project.

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