NDARC Technical Report No. 261 (2006)

EXECUTIVE SUMMARY

Aims: This report examines trends in drug-related hospital separations (including use, dependence, psychosis and withdrawal) in Australia during the period 1993 to 2004. The report presents data on characteristics of those people being treated in hospital for drugrelated reasons, details of their hospital stay, analysis of which other drugs co-occur with each drug type, and analysis of the non drug-related treatment received while in hospital in conjunction with drug-related treatment.

Method: Hospital separation data from the National Hospital Morbidity Database (NHMD), coded according to the International Statistical Classification of Disease and Related Problems - 9th revision, clinical modification (ICD-9-CM) and the 10th revision, Australian Modification (ICD-10-AM) were analysed for the period 1993 to 2004.

Coding of hospital separations occurs after a patient has been discharged. The coding of a patient’s hospital stay (the “hospital separation”) therefore refers to the conditions that are significant in terms of the treatment and investigations required, and resources used, rather than the problem for which they may have been nominally admitted to hospital.

Separations with a diagnosis (either principal or additional) related to opioids, amphetamines, cocaine and cannabis were analysed. Numbers and rates (per million persons) of separations with a principal diagnosis related to each drug type were assessed. Gender, age group, length of stay, and funding source were also assessed by drug type.

Results
a) Trends in opioid-related hospital separations
Hospital separations with a principal diagnosis related to opioids (referred to as “opioidrelated separations”) steadily increased during the period 1993/94 to 1998/99. There was a dramatic decrease in these separations in 2001/02, coinciding with a marked reduction in heroin supply in Australia at this time. NSW recorded the highest number of separations during the eleven-year period, followed by VIC and QLD. NT recorded the lowest number of opioid-related separations.

Separations with a principal diagnosis of opioid dependence showed a similar pattern, with separations more than doubling between 1993 and 2000, and then halving from 2000/01 to 2001/02. NSW recorded the highest numbers of opioid dependence separations followed by VIC and QLD.

Opioid-related separations were highest among the 20 to 29 year age group. Increases between 1993 and 2000 were most pronounced among this group, with a dramatic decline occurring in 2000/01. This pattern was also evident among the 10 to 19 and 30 to 39 year age group although at a lower level. There has been a steady increase in opioid-related separations among the 40 to 49 year age group, and unlike the younger age groups, there was little if any decrease in separations in 2000/01 among either the 40 to 49 or 50 to 59 year olds. These trends were mirrored in separations where opioid dependence was the principal diagnosis. Males accounted for just over half (58%) of the opioid-related separations recorded in Australia in 2003/04.

Principal diagnoses that were recorded in conjunction with opioid mentions (i.e. separations where opioids were coded as either the principal or as an additional
diagnosis) were predominantly physical health problems, reflecting the relatively poor general health of these users. An increasing proportion of opioid mentions had principal diagnoses of mental disorders, while principal diagnoses of pregnancy complications, other drug and alcohol related problems, and injury accompanied smaller proportions of opioid mentions.

Cannabis was the drug most commonly recorded as an additional diagnosis in conjunction with opioid-related separations in 2003/04. Amphetamines were recorded in a smaller number of separations, while cocaine was rarely mentioned in conjunction with opioid-related separations.

Approximately three-quarters of the hospital stays for opioid-related separations in 2003/04 were one week or less in duration, and the majority were for patients receiving public hospital services.

b) Trends in cocaine-related hospital separations
Hospital separations with a principal diagnosis related to cocaine (referred to as “cocainerelated separations”) steadily increased from 1993/94 to 2001/02, with separations more than tripling in this time. NSW recorded the highest number of cocaine-related separations and accounted for the majority of the national total. Other jurisdictions recorded comparatively fewer cocaine-related separations during the eleven-year period.

Separations with a principal diagnosis of cocaine dependence also increased, with peaks occurring in 1998/99 and 2001/02, and declining in 2002/03. They increased slightly in 2003/04. NSW had the highest number of cocaine dependence separations and again accounted for the majority of the national total.

Numbers of cocaine-related separations were small across all age groups, with less than 100 per year being recorded. Separations were highest among the 20 to 29 year age group. Sharp increases were evident among this group between 1999 and 2002, followed by a dramatic decline in 2002/03. They subsequently increased in 2003/04. A similar pattern was evident among the 30 to 39 year age group. Trends for cocaine-related separations were mirrored in those for cocaine dependence, with a sharp increase occurring among the 30 to 39 year age group in 2003/04. Males accounted for more than three-quarters (80%) of the cocaine-related separations recorded in Australia in 2003/04.

The most common principal diagnoses that were recorded in conjunction with cocaine mentions (i.e. separations where cocaine was coded as either the principal or as an additional diagnosis) was for other drug or alcohol problems, particularly opioid and alcohol dependence. A substantial proportion of principal diagnoses was due to a physical health problems, and increasing proportions were accounted for by mental disorders.

Amphetamines were most commonly recorded in conjunction with cocaine-related separations in 2003/04, while cannabis and opioids were only recorded in a minority of cocaine-related separations.

The majority of hospital stays for cocaine-related separations in 2003/04 were for one day only. The funding source reported for the majority of these separations in NSW and VIC (where they were highest) was private health insurance.

c) Trends in amphetamine-related hospital separations
Hospital separations with a principal diagnosis related to amphetamines (referred to as “amphetamine-related separations”) showed a steady increase over the eleven-year period, tripling nationally between 1993/94 and 2001/02. They have remained stable for the past few years at a higher level. NSW recorded the highest number of amphetaminerelated separations, followed by QLD and WA. NT and the ACT recorded low numbers of amphetamine-related separations.

Trends in separations with a principal diagnosis of amphetamine dependence mirrored amphetamine-related separations, with NSW recording the highest numbers, followed by QLD.

Amphetamine-related separations were highest among the 20 to 29 year age group followed by the 10 to 19 year age group. Steady increases were recorded across all age groups during the eleven-year period. Separations for amphetamine dependence were also highest among the 20 to 29 year age group followed by the 30 to 39 year olds. Increases in dependence separations were evident across all age groups except the 10 to 19 year olds, where separations have decreased slightly over the past four years. Males accounted for just over half (59%) of the amphetamine-related separations recorded in Australia in 2003/04.

An increasing proportion of amphetamine mentions (i.e. separations where amphetamines were coded as either the principal or as an additional diagnosis) were
accompanied by mental disorders, particularly mood and psychotic disorders. These increases were largely due to increasing diagnosis of the psychotic disorders. This should be interpreted with caution, however, as it may not reflect an increase in the incidence of psychotic disorders but, rather, that the same people are presenting to hospital on several occasions with these problems. A substantial proportion of other drug and alcohol problems (particularly drug-related psychosis, and alcohol and opioid dependence) accompanied amphetamine mentions, while smaller proportions were accompanied by a broad spectrum of physical health problems.

Cannabis was the drug most commonly recorded with amphetamine-related separations, followed by opioids. Cocaine rarely co-occurred with amphetamine-related separations. Approximately two-thirds (63%) of hospital stays for amphetamine-related separations in 2003/04 were for one day only. Among those separations that were for more than one day, the majority were for no more than two weeks (14 days). The majority of amphetamine-related separations in 2003/04 were for patients receiving public hospital services.

d) Trends in cannabis-related hospital separations
Hospital separations with a principal diagnosis related to cannabis (referred to as ‘cannabis-related separations’) steadily increased between 1993/94 and 2001/02 and have remained relatively stable since that time. NSW had the highest number of cannabis related separations during this period followed by QLD. TAS, the NT and the ACT all had relatively low numbers of cannabis-related separations.

Separations with a principal diagnosis of cannabis dependence also increased in the period leading up to 2001/02, before a slight decline in 2002/03. Cannabis dependence separations in NSW accounted for over half of the national total, while VIC and QLD accounted for 20% and 15% respectively. SA, TAS, the NT and the ACT recorded comparatively lower numbers of cannabis dependence separations.

Cannabis-related separations were highest among the 20 to 29 year age group, followed by the 10 to 19 year olds. Cannabis separations steadily increased among the 20 to 29 year age group during the period, but they declined among the 10 to 19 year age group in 1999/00 and have remained at that lower level over the past five years. Separations also steadily increased among the 30 to 39 year age group. They remained low among the older age groups (the 40 to 49 and 50 to 59 year age groups). Males accounted for approximately three quarters (72%) of the cannabis-related separations in Australia in 2003/04.

An increasing proportion of hospital separations with mentions of cannabis were accompanied by principal diagnoses of mental disorders, particularly psychotic and mood disorders. Substantial proportions of hospital separations where cannabis was mentioned were also accompanied by other drug problems, particularly alcohol and opioid dependence and, to a lesser extent, drug-related psychosis. Smaller proportions of cannabis mentions were accompanied by physical health problems, while there were decreases in the proportions accompanied by poisoning by drugs, medicaments and biological substances.

Amphetamines were the drug type most commonly co-occurring with cannabis-related separations, while opioids co-occurred in small minorities of these separations. Cocaine was rarely reported in conjunction with cannabis-related separations.

Just under half (45%) of the hospital stays in 2003/04 for a principal diagnosis related to cannabis were for one day only. Among those separations that were for more than one day (703 separations), the majority (91%) were for no more than 3 weeks duration (21 days). The majority of cannabis-related separations in 2003/04 were for patients receiving public hospital services. However, the funding source reported for over onethird (37%) of NSW separations was private health insurance.

e) Trends in drug-related psychosis separations
Hospital separations with a principal diagnosis of drug-induced psychosis (referred to as ‘drug-related psychosis separations’) have increased over the eleven-year period at a national level. Drug-related psychosis separations were most commonly recorded in NSW and QLD. NSW has seen a continued increase in these separations and accounted for approximately one-third of the national total, while QLD separations started to decline in 2001/02, accounting for approximately 25% of the national total.

Hospital separations with a principal diagnosis of amphetamine psychosis (referred to as ‘amphetamine-related psychosis separations’) accounted for the largest proportion (approximately half) of all drug-related psychosis separations between 1999/00 and 2003/04, followed by cannabis. There was a gradual but steady increase in amphetamine-related psychosis separations during this period, with NSW recording the highest number, followed by QLD. NSW, QLD, WA and SA all recorded increases in amphetamine-related psychosis separations. Cannabis-related psychosis separations (i.e. with a principal diagnosis of cannabis-induced psychosis) remained relatively stable during the five-year period. Cocaine-related psychosis separations (i.e. with a principal diagnosis of cocaine-induced psychosis) accounted for less than 2% of principal drugrelated psychosis separations between 1999 and 2004.

Amphetamine-related psychosis separations were highest among the 20 to 29 year age group, followed by the 30 to 39 year age group. These separations steadily increased among both groups between 1999 and 2004, and separations among the 30 to 39 year age group accounted for the highest proportion of all drug related psychosis separations. Cannabis-related psychosis separations were also highest among the 20 to 29 year age group, and remained relatively stable during the five-year period. A similar trend was evident among the 10 to 19 year olds. There was a slight increase in cannabis-related psychosis separations among the older groups (the 30 to 39 year age group and the 40 to 49 year age group) although numbers were small. Cannabis-related psychosis separations among the 10 to 19 year age group accounted for the highest proportion of all drug-related psychosis separations. Males accounted for approximately two-thirds of the amphetamine-related psychosis separations and three-quarters of the cannabis-related psychosis separations in 2003/04.

Just under half (40%) of the hospital stays in 2003/04 for a principal diagnosis related to amphetamine-induced psychosis were for one day only. Among those separations that were for more than one day (967 separations), the majority (94%) were for no more than three weeks (21 days). The majority of these separations were for patients receiving public hospital services. In VIC however, the funding source reported for one-third of these separations was private health insurance.

Hospital stays for cannabis-related psychosis in 2003/04 were slightly longer than for the other drug-related presentations, with just under one-quarter (23%) being for one day only. Among those separations that were for more than one day (888 separations), the majority (94%) were for no more than four weeks (28 days). The majority of these separations were for patients receiving public hospital services.

f) Trends in drug withdrawal separations
Separations with a principal diagnosis of drug withdrawal (‘drug withdrawal separations’) increased between 1994/1995 and 2000/01, then decreased dramatically in 2001/02. They have remained stable in the past few years. Drug withdrawal separations in NSW were the highest during the eleven-year period, accounting for just under half of the national total. VIC had the next highest number of separations for drug withdrawal followed by QLD. All jurisdictions recorded decreases in drug withdrawal separations in 2001/02, with the exception of TAS, the NT and the ACT, which all recorded very small numbers during the eleven-year period.

Opioids accounted for the majority of drug withdrawal separations for the period 1999 to 2004, with NSW recording the highest number during this time. Opioid withdrawal separations dropped dramatically in 2001/02 across most jurisdictions. Amphetamine withdrawal separations accounted for up to 17% of all drug withdrawal separations between 1999 and 2004, and remained relatively stable at a national level and in most jurisdictions until 2003/04, when they increased slightly. NSW and QLD recorded the highest amphetamine withdrawal separations, with NSW separations almost doubling between 2002/03 and 2003/04. The NT, the ACT and TAS recorded very small numbers of amphetamine withdrawal separations during the five year period. Cannabis accounted for between 5% and 15% of drug withdrawal separations, and although numbers have remained low, they have increased at a national level over the past couple of years. Cocaine accounted for less than 2% of drug withdrawal separations during the five-year period.

Due to relatively small numbers of withdrawal separations recorded for amphetamine, cannabis and cocaine, detailed analyses were only conducted on opioid withdrawal separations. These separations were highest among the 20 to 29 year age group. Dramatic decreases were evident among the younger age groups (the 20 to 29 year and 10 to 19 year age groups) in 2001/02, and have since remained lower. Decreases in opioid withdrawal separations among the older age groups (the 30 to 39 year and 40 to 49 year age groups) were less pronounced at this time. Although numbers of separations among the 50 to 59 year age group were relatively small, they have been increasing since 2001/02. Males accounted for just over half of the opioid withdrawal separations recorded in Australia in 2003/04.

Just over half (54%) of the hospital stays in 2003/04 for a principal diagnosis related to opioid withdrawal were for one day only. Among those separations that were for more than one day (253 separations), the majority (97%) were for no more than two weeks (14 days).

The majority of hospital stays for opioid withdrawal in 2003/04 were for one week or less in duration, and they were primarily for patients receiving public hospital services.

Discussion
Opioid-related separations were the most frequent illicit drug-related separations occurring in Australia over the eleven-year period. A substantial proportion (up to 54%) of opioid mentions was accompanied by a broad spectrum of physical health problems, which is indicative of the relatively poor physical health of this group of drug users, and the provision of primary health care to this group should remain a priority.

Opioid-related separations declined dramatically in 2001/02, the period of the heroin shortage. The decline was predominantly evident among the younger age groups, while the older age groups recorded steady increases in opioid-related separations during the eleven-year period. This suggests that the heroin shortage had a differential impact on illicit drug-related harms among different age groups and confirms the findings of previous research looking at this issue (Degenhardt, Day, Conroy et al., 2005b) and also confirms trends in data on fatal opioid overdoses in Australia (Degenhardt, Roxburgh, Black et al., 2006a). While there was a dramatic decline in opioid-related separations, they remain the highest across the drug types, and continue to place a burden on the public health system, given that the majority of these separations are for patients receiving public hospital services.

Amphetamine-related separations were the next highest in number, and increased over the eleven-year period. Separations for amphetamine dependence and withdrawal accounted for a small minority of amphetamine-related separations while separations for amphetamine-related psychosis accounted for just under half of all amphetamine-related separations in 2003/04, with steady increases evident over the past five years.

These findings suggest that amphetamine users are more likely to present to hospital when they are in crisis (e.g. when they are experiencing significant psychotic symptoms) than for problems associated with dependent amphetamine use. Strategies to encourage amphetamine users experiencing problems related to their use to seek treatment need to be developed and implemented, as effective treatments do exist for the problematic use of amphetamine. Education about the risks associated with amphetamine use (such as psychosis), and how to manage these risks, also needs to be delivered to users.

Problematic amphetamine users may present a range of challenges to frontline health workers, due to aggressive and hostile behaviour often associated with these presentations. Continued training of frontline health workers (e.g. Needle and Syringe Program (NSP) and hospital staff) on the management of amphetamine-related psychosis is required in an attempt to reduce the number of cases that present to hospital, and to minimise the impact on hospital resources when cases do present to hospital.

Cannabis-related separations have remained relatively stable over the past two years following an increasing trend between 1993 and 2002. Numbers of cannabis dependence separations are still comparatively smaller than those for opioid dependence (despite the decrease in opioid-related separations from 2001/02). Increases among the older age groups were evident while dependence separations declined among the 10 to 19 year age group.

Cannabis-related psychosis separations also remained relatively stable over the past five years, however, increasing proportions were accounted for by the younger 10 to 19 year age group. Younger cannabis users appear to have more acute problems associated with their cannabis use than the older users, which may be related to heavier use patterns reported among younger users in Australia (Australian Institute of Health and Welfare, 2005). Up to half of the cannabis mentions were primarily due to mental disorders.

Education interventions focused upon cannabis use need to provide credible and balanced information about the risks (both short and long term) of regular cannabis use. Effective psychological interventions do exist for cannabis dependence, and this should be disseminated to health workers as well as users who may wish to seek help.

Cocaine-related separations were much lower than those for other drugs, with increases coinciding with the heroin shortage in 2001. These separations were predominantly recorded in NSW, and were highest among the older age groups, and up to one-third of cocaine mentions were accompanied by other drug and alcohol problems. These findings suggest that small numbers of predominantly older users present for treatment for cocaine use, and are likely to have problems with other drug and alcohol use.

Training of health workers in the diagnosis, assessment and treatment of co-morbid mental health problems is also crucial, given the high prevalence of co-morbid presentations.

The National Hospital Morbidity Database is a useful data source for monitoring illicit drug-related harms in Australia, and it maps well to other data sources, such as seizure and arrest data, and reports from injecting drug users (IDU). Continued monitoring of this data would provide important information about trends in drug-related harms in Australia, as well as the context within which emerging trends can be understood. Finally, analysis of this data, in conjunction with other available data sources, would provide a reliable framework within which to inform evidence-based drug policy in Australia.

Citation: Roxburgh, A. and Degenhardt, L. (2006) Hospital stays related to illicit drugs in Australia, 1993-2004, Sydney: National Drug and Alcohol Research Centre.

Resources

Date Commenced
01 Dec 2006
Resource Type
Technical Reports