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1. Hospital statistics in NSW
All NSW public hospitals, public psychiatric hospitals, public multi-purpose services, private hospitals and private day procedure centres in NSW report data on patients admitted for care to the NSW Ministry of Health. Patient separations from developmental disability institutions and private nursing homes are not included. These reported data, from about 400 different facilities in NSW, are called the NSW Admitted Patient Data Collection (APDC).
The collection also includes data relating to NSW residents hospitalised interstate (see below in Imputation for more details) and in Commonwealth Department of Veterans’ Affairs facilities.
Each reporting facility has its own Patient Administration System, there are five types of these in NSW: HNMA Millenium (administered by Cerner), WinPAS, iPM (I-Soft), HOSPAS (legacy system being phased out and replaced with other systems) and ISCOS, which is the Inpatient Statistics Collection On-line System used by private hospitals. Data from the PAS systems are loaded into the Health Information Exchange (HIE) in a standard format. The HIE is the data warehouse for the whole NSW health system maintained by the NSW Ministry of Health which is accessed by authorised staff across the health system and in the NSW Ministry of Health. Data from the HIE are alos extracted and loaded onto the Health Outcomes Information and Statistical Toolkit (HOIST) warehouse, administered by the Centre for Epidemiology and Research and used for this report.
2. Hospitalisation rate definition
A hospitalisation rate is an estimate of the proportion of a population that was hospitalised during a specified period. It is expressed in this report as the number of hospitalisations per 100,000 population per year (person-years). Age and sex standardisation (also called ‘adjustment’) adjusts for differences in the age and sex structure of populations and is performed to make rates comparable between different sub-populations in the same geographic area; in the same population over time; or between different geographic areas at the same time (for example between different States and Territories or different Local Health Districts). This assists in interpreting variations in patterns of hospitalisations between groups and over time after controlling for factors such as age which are commonly associated with increased disease rates.
Hospitalisation rates in this report are standardised to the 2001 Australian standard population.
3. The Admitted Patient Data Collection and this report
The Admitted Patient Data Collection (APDC) is a census of all inpatients treated in NSW and includes data on NSW residents treated in other states. The APDC was, up to 2002, called the Inpatient Statistics Collection. The APDC contains approximately 70 variables and is based on a financial year cycle beginning on 1 July and ending on 30 June of the following year.
The APDC data used in this report are the HOIST (Health Outcomes Information and Statistical Toolkit) data warehouse, maintained by the Centre for Epidemiology and Research. The APDC data is extracted from the Health Information Exchange (HIE) and undergoes a quality assurance and standardisation process before being loaded onto HOIST in a SAS datset format.
Further infromation on the APDC and HOIST is available in this report in Methods tab under The Admitted Patient Data Collection title.
4. Use of selected variables of APDC in this report
4.1 Principal diagnosis and additional diagnoses coded to the ICD-9-CM and ICD-10-AM
Each hospital episode in the APDC is described by a principal diagnosis and additional diagnoses, which are coded using the International Statistical Classification of Diseases and Related Health Problems: ICD-9-CM (up to June 1998) and ICD-10-AM (from July 1998 onwards). Please refer to a separate Methods section on Principal and additional diagnoses for a detailed discussion (this section accompanies selected indicators that include principal and additional diagnoses, for example diabetes hospitalisations).
In this report the count of hospitalisations for a condition is based mainly on principal diagnosis (except for 'comorbidities', which are based on additional diagnoses; and injury and poisoning which are based on ‘external cause of injury’. See Methods for injury and poisoning indicators). If an indicator contains analysis of data in additional diagnosis fields as well, this is clearly stated in the title of an indicator and in the Notes. The notes specify how many additional diagnosis fields were included in the analysis.
The number of additional diagnoses that are included in the hospital records is restricted to conditions which fulfil several requirements, including direct relevance to the treatment and management of the principal diagnosis. This ensures that only the most resource intensive or clincially relevant conditions are listed for that hospitalisation rather than all comorbidities that a patient may have. Data on additional hospital diagnoses cannot therefore be used to estimate the prevalence of a condition in the community.
4.2 Procedures coded to Australian Classification of Health Interventions
Procedures performed in Australian hospitals are coded in medical records using the Australian Classification of Health Interventions (ACHI) published by the National Centre for Classification in Health. This classification is based on the Commonwealth Medicare Benefit Schedule and refers to anatomy rather than surgical specialty.
Up to 30 June 1998 the ICD-9-CM Procedure Classification was used in Australia. This was based on WHO Surgical procedures (edition 5) and was not revised and carried beyond 1998 by the WHO due to the rapid advancements in the field of procedures (National Coding Centre 1996).
On 1 July 1998, both the ACHI and the ICD-10-AM were introduced in NSW. They are revised every two years. The ICD-10 is the WHO classification but the AM suffix stands for Australian Modification which adds detail necessary to describe practice in Australian hospitals. The ICD-10-AM is fully compatible with ICD-10 (NCCH 2006).
Up to the fourth edition of ICD-10-AM in 2004, the ACHI was published as a part of the ICD manuals (volume 3 and 4), from the fifth edition in 2006 the titles of the ACHI publication emphasise that this is a classification independent from the ICD.
Both ICD-9-CM Procedure Classification (up to and including 1997-98) and Australian Classification of Health Interventions (from 1998-99 onwards) are used in this report.
4.3 Episode of care based count of hospitalisations
The count of hospitalisations in this report is based on an episode of care from 1 July 1998 (ISC EOC datasets on HOIST). A patient can have several episodes of care during one hospital stay, that is, between the formal admission and the formal discharge (separation) from hospital.
The episode of care is defined by a service category. An episode of care starts when the hospital stay starts or when the service category changes. There are ten service categories: acute care, rehabilitation care, palliative care, maintenance care, newborn care, other care, geriatric evaluation and management, psychogeriatric care, organ procurement-posthumous and hospital boarder.
A new episode of care starts also when a patient is on leave from hospital: more than 4 days away in any hospital and more than 10 days away in psychiatric hospitals.
4.4 Overnight and day-only hospital stays are included
Both overnight and day-only hospitalisations are included in this report, unlike in the national reporting on hospital statistics (AIHW Health services series no. 40. Cat. no. HSE 107 2011).
The only exception are the count and rate of hospitalisation for falls in elderly (persons aged 65 years and over) in NSW, where the day-only hospitalisations are excluded from the key indicator reports in NSW. The data reported as the count and rate of hospitalisation for falls in elderly in NSW include only overnight (and longer) hospitalisations in all NSW performance reporting. However, in this report, an analysis of day-only hospitalisations and the total of overnight and day-only hospitalisations are also included in the relevant indicator for comparison and completeness.
4.5 Full census of hospitalisations from 1993-94 and sampling factor prior to 1993-94
In 1993-94 the APDC (then called the Inpatient Statistics Collection) was a fully enumerated survey (that is a census) for the first time. Datasets containing financial years earlier than 1993-94 are based on estimates from a sample of all inpatient data in some hospitals, partiularly in rural areas, and their use in analysis requires the inclusion of a sampling factor weighting variable.
4.6 Separation date determines the year of hospitalisation
The main record file of the hospital stay for a patient is created or completed on separation from hospital when all relevant documentation is made available to hospital record departments. Consequently, the main reason for hospitalisation (principal diagnosis) completed at separation, may be different from the admitting diagnosis. The hospitalisation is counted in the year when the separation took place even if the hospitalisation period occurred predominantly in the previous financial year. For example a patient discharged on 1 July after a 4 week hospital stay would be counted as hospitalised in the new financial year.
4.7 Imputation of interstate hospitalisations in the last year of data
At the time when the NSW Ministry of Health completes the Admitted Patient Data Collection for the previous financial year data on hospitalisations of NSW residents in other states are usually not available and so interstate hospitalisations for the latest year is always ‘imputed’ from the previous three years in this report. This imputation process estimates the number of hospitalisations occurring in other states for each diagnosis in previous years and adds these numbers to the latest year of data. When the actual data become available, the number and rates for the latest year are re-calculated.
4.8 Summary of major changes in the hospital data on HOIST
1988-89: Hospital data included from the Inpatients Statistics Collection (ISC) counted on the basis of a "period of stay" in hospital (ie multiple episodes of care). ICD-9-CM used and sampling from some hospitals (requiring a sampling factor for weighting numbers in these hospitals).
1993-94: Admitted Patient Data Collection (APDC) is a fully enumerated census of hospitalisations.
1998-99 onwards: APDC starts to be counted as episodes of care. ICD-10-AM replaces ICD-9-CM; and Australian Classification of Health Interventions replaces ICD-9-CM Procedure Classification.
Imputation for interstate hospitalisations: The latest year of data (number and rates) are ‘imputed’ for missing interstate hospitalisations for NSW residents. The actual number of interstate hospitalisations is included when available.
5. Differences between figures published by the AIHW and the NSW Ministry of Health and other institutions
5.1 Differences in publication schedules
The APDC dataset is continuously updated because it is not uncommon to receive additional records or additional information on records already supplied well after the close of a financial year. Consequently data on hospitalisations in NSW from different sources, such as this report and the AIHW report, will always differ slightly due to different publication schedules.
5.2 Imputation of interstate hospitalisations in the latest year of data
In this report imputation methods are used to estimate the number of hospitalisations for NSW residents occurring elsewhere in Australia in the latest year due to a lag in receiving this information (see above). In some editions of the report two last years of data had to be imputed. Refer to Notes in the indicator for confirmation. Estimates may vary slightly from the actual numbers in other editions of this report or other reports for this reason. The actual number of interstate hospitalisations is included when available.
5.3 Definition of hospitalisation
Both overnight and day-only hospitalisations are included in this report, unlike in the national reporting on hospital statistics (AIHW Health services series no. 40. Cat. no. HSE 107 2011).
5.4 Different projected populations
For the calculation of rates, the NSW Ministry of Health uses population projections based on the NSW Health Population Projection Series, prepared by the Statewide Services Development Branch of the NSW Ministry of Health in collaboration with the NSW Department of Planning. Refer to Methods in Population-Demography topic for further information on projected populations and other issues mentioned here. The rates in this report are expressed as a number per 100,000 population.
Rates published by the Australian Institute of Health and Welfare may be expressed differently (per 1,000 or 10,000 population) and use different projected population estimates for NSW. The population estimates,which are not projected, are likely to be the same, as these are based on the estimated residential populations published by the ABS.
6. Other datasets holding data on activity in hospitals
The APDC datasets contain information on inpatient hospital activity. Emergency department data and Outpatient activity data are also available to report on hospital activity. The data from Emergency departments have been used in this report and the dataset is discussed separately (see topic Emergency departments). Other datasets have not been used in this report yet.
7. References
Australian Institute of Health and Welfare. Australian hospital statistics 2009–10. Health services series no. 40. Cat. no. HSE 107. Canberra: AIHW, 2011. Available at http://www.aihw.gov.au/publication-detail/?id=10737418863 (Cited on April 2011).
National Centre for Classification in Health. The International statistical classification of diseases and related health problems, 10th Revision, Australian Modification (ICD-10-AM). Australian Coding Standards. Sydney: NCCH, 2006.
National Coding Centre. The Australian version of the International Classification of Diseases, 9th revision, clinical modification (ICD-9-CM). Sydney: University of Sydney, 1996.
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Changes to coding of diabetes in the Admitted Patient Data Collection in NSW since July 1998 and impact of the changes on analysis of diabetes hospitalisation trends
Summary
• Coding of diabetes in primary diagnosis field has been stable between July 2000 and June 2010. The records within this period are expected to reliably reflect hospitalisation for diabetes (with and without complications) as the primary reason for admission between 2000-01 to 2009-10 inclusive. A substantial change was introduced in July 2010.
• Coding of diabetes in additional diagnosis has been very unstable throughout the whole period of hospitalisation census in NSW (that is since 1989-90). Coding changed 7 times, the first change took place in July 1998 and the seventh in July 2010. Consequently, monitoring of prevalence of diabetes in the community, or monitoring of hospital admission practices by using records of diabetes in additional diagnosis field is not appropriate.
• The period in NSW between July 2004 and June 2005 (that is, financial year 2004-05) is the time when all admissions with diabetes were accounted for, in both primary and additional diagnosis, and the distinction between diabetes with and without complications was reflecting the true status of diabetes. Consequently, data from this one year are the most reliable to use for estimates of the prevalence of diabetes in the community and the distribution of hospitalisations for diabetes with and without complications in NSW in the first half of 2010s.
Details of changes
There have been six changes concerning coding of diabetes in the Admitted Patient Data Collection (APDC) [or Inpatient Statistics Collection (ISC) as it was called till 2002] in NSW since 1998. (A detailed discussion of the APDC can be found in Methods accompanying indicators in the topic Hospitalisation overview)
1. The first change was due to the change of the version of the classification system from International Classification of Diseases version 9 (NCC 1996) to version 10 (NCCH 1998) in July 1998.
1.1. Coding of diabetes has not been affected by that change. Note that the trends continue undisturbed over the 1998-99 data point on relevant graphs.
2. The second change was introduced in July 1999. It required that diabetes (with or without complications) is included in the case record as additional diagnosis only if it affected hospitalisation (see in 2.1 below). This requirement applied to all conditions already from 1998 with the exception of hypertension, Parkinson disease and diabetes. In Australia in July 1999, this exception was removed [Australian Coding Standard (ACS) 0002] by the National Centre for Classification in Health.
2.1. The Australian Coding Standard 0002, volume 5 [each edition from 1998 up to and including 2010 (NCCH 2010)]:
‘For coding purposes, additional diagnoses should be interpreted as conditions that affect patient management in terms of requiring any of the following:
(.) therapeutic treatment, (but from July 2008 the following has been added: ‘commencement, alteration or adjustment of therapeutic treatment’ see point 6 for discussion)
(.) diagnostic procedures
(.) increased nursing care and /or monitoring.’
2.2 This change had some effect and the rate of diabetes in additional fields (both with and without complications) was reduced in NSW. At that time 20 diagnosis fields were available in the electronic APDC system in NSW.
3. The third change, in July 2000 concerned only diabetes with complications (in primary and additional diagnosis fields). It stated (ACS 0401) that it was no longer required for clinicians to make a clear ‘cause – effect’ connection between diabetes and another co-existing condition for medical coders to be required to code diabetes with complication, as long as the complication was on the ‘approved ICD list’. A separate code for the co-existing condition is also to be used in order to describe the condition more fully.
3.1. For example, a statement in clinical notes to the effect that there is increased intra-abdominal fat deposition leads to the use of code E1x.72: ‘diabetes mellitus with features of insulin resistance’. Renal diseases must be matched with ‘diabetes with renal complication’ (E1x.2x).
3.2. The remaining restriction, that is that only indexed co-existing conditions (listed in ICD manuals) can be classified to ‘with complication’ categories and that they must be matched with an appropriate category of ‘diabetes with complication’ code, had led to some dissatisfaction with the coding system for diabetes. This is because there is a perception in Australia that the existing list is incomplete, especially in relation to cardiovascular conditions (AIHW workshop on Ambulatory care sensitive conditions in 2008, personal correspondence).
3.3. This change had a considerable effect on rates. The rates for diabetes with complications (both in principal and additional diagnosis fields) rose and the rates for diabetes without complication decreased (both in principal and additional diagnosis fields).
3.4. This effect, where records flowed from diabetes without complications to diabetes with complications, was desirable. It resulted in better accounting for cases of hospitalisations with diabetes with complications (co-existing, not necessarily caused by diabetes and those caused by diabetes, which often could not be ascertained), and consequently improved scope for monitoring prevalence of diabetes with complications.
4. The fourth change in July 2004 concerned only NSW. It reversed the changes from July 1998 and July 1999 concerning rules governing additional diagnoses. That is, from July 2004 in NSW, all conditions diagnosed in a patient and recorded in a patient file when hospitalised, including diabetes, had been coded in the case’s APDC record regardless whether they impacted on hospitalisation or not. At that time there were 55 diagnosis fields available in the electronic APDC system in NSW (although only the first 15 or so were ever filled in).
4.1. This change had a dramatic effect on the rates for diabetes with complications (which increased) and without complications (which decreased) in additional diagnosis in NSW. The change can be interpreted as the second correction towards achieving a full accounting of diabetes with complications in hospitalised persons in NSW for surveillance and as such it was desirable.
4.2. The ‘exchange’ of numbers between records with diabetes with and without complications can be interpreted as follows. Prior to July 2004, coders coded diabetes without complications in cases where diabetes itself and not a co-existing complication was attended to during hospitalisation (and hospitalisation occurred for another reason altogether, recorded as principal diagnosis, neither diabetes nor its complication).
4.3. For example, a patient could have had insulin levels measured and medication could have been dispensed accordingly, but renal, neurological or any other complications were not attended to directly. Before July 2004, this was regarded as ‘diabetes without complications’ from the point of view of hospital stay.
4.4. This confusing coding practice was employed to fulfil the requirement that only diagnosis impacting on hospital stay is acknowledged in the record. It was an anomaly well known to coding experts in the Department prior to July 2004.
4.5. After July 2004, the increase in the records with diabetes with complications in additional diagnosis was greater than it could be explained by the flow of records from diabetes without complications. This additional increase was likely due to the inclusion of diabetes with complications in cases where diabetes was previously excluded as not relevant to a hospital stay.
5. The fifth change, in July 2005, reversed the change from July 2004 and concerned additional diagnoses only. Problems involving information technology were cited as the reason for reversing the change made in 2004. Apparently, electronic APDC systems in NSW could not reliably distinguish between and filter diagnoses coded as relevant from those coded as not relevant to a hospitalisation.
5.1. It should be noted that the 2004 change was contrary to the Australian Coding Standards and in the absence of appropriate filtering of records the NSW health system could not fulfil its national reporting obligations. The change introduced in 2005 was therefore necessary, to ensure that the data collection was properly supporting the system of Diagnosis Related Groups and financial monitoring. At the same time, however, this change curtailed the efforts to make the APDC system more accommodating to reporting on population health concerns.
5.2. The change from July 2005, that is the one that returned the NSW diabetes coding in hospital statistics to the national standard, did not bring the expected reduction in the numbers and rates of diabetes in additional diagnosis in the NSW hospital statistics. The rates in 2005-06 were higher than in 2004-05 and continued to rise afterwards.
5.3. The reason for this lack of change in the trend was that the diabetes was still coded even if its impact on hospital stay was limited to monitoring. That is even if only blood glucose test was performed, diabetes was still coded as relevant to hospital stay.
6. In July 2008 the Australian Coding Standard 0002 concerning additional diagnoses was revised (see the first dot point in point 2.1 above) and the requirement for relevancy to hospital stay was strengthened. This was the sixth change. The new definition of additional diagnosis directs coders to include diabetes as an additional diagnosis only if a substantial alteration to the treating regime took place (NCCH 2008). This change had a dramatic effect on the numbers and rates of diabetes in additional diagnosis field in the NSW hospital statistics, with a 54% reduction in comorbidity rates between 2007-08 and 2008-09.
7. In July 2010 the Australian Coding Standard 0401 concerning diabetes mellitus and impaired glucose regulation was revised and a major change was introduced. The coding of diabetes was changed to follow the rules of coding of principal (ACS 0001) and additional diagnoses (ACS 0002) applying to all other hospitalisations thus removing an anomaly known as ‘a reverse index pathway’ coding concerning diabetes up to that point. This change meant that the coding of the principal diagnosis was to take place first and additional diagnoses were to be coded then in all hospitalisations that involved diabetes. This change affected both the coding of principal diagnosis and additional diagnoses. This was the seventh change.
7.2. For example, a cataract or ulcer being treated as the main reason for the hospitalisation in a person with a history of diabetes would have previously been coded as diabetes with a matching complication in the principal diagnosis and a cataract or ulcer would have been included in additional diagnosis (‘a reverse index pathway’). Since July 2010 a cataract or ulcer are coded as principal diagnoses and diabetes is included as additional diagnosis if it fulfils the criteria of additional diagnosis, that is if it substantially impacts on admission (as explained in point 2.1 and 5 above) or if a ‘cause and effect’ relationship between diabetes and a complication is clearly established in medical notes (see points 3. and 3.1) and diabetes can be classified as a problem or underlying condition and included in additional diagnosis under the rules of ACS 0002.
7.3. This change affected diabetes in both principal and additional diagnoses. In the principal diagnosis the change had a dramatic effect on hospitalisation rates, with an almost 60% drop in rates between 2009-10 and 2010-11.
7.4. This change has had a negative impact on the use of hospital data to monitor the burden of diabetes in the population. The long term trend of hospitalisations for diabetes in a principal diagnosis no longer reflects the rising prevalence of Type 2 diabetes. Many cases of complications of diabetes can be still ascertained via additional diagnoses. However, many complications have not been included as additional diagnoses since July 2010. These complications are, for example, where the ‘cause and effect’ has not been specifically mentioned in the clinical notes, but does exist, or conditions where the ‘cause and effect’ does not apply but the principal cause of the hospitalisation has been worsened by co-existing diabetes (conditions included on the NCCH approved complications list that co-exist with diabetes, see point 3.1).
References
National Centre for Classification in Health. The International statistical classification of diseases and related health problems, 10th Revision, Australian Modification (ICD-10-AM). Seventh edition. Australian Coding Standards Sydney: NCCH, 2010.
National Centre for Classification in Health. The International statistical classification of diseases and related health problems, 10th Revision, Australian Modification (ICD-10-AM). Sixth edition. Australian Coding Standards Sydney: NCCH, 2008.
National Centre for Classification in Health. The International statistical classification of diseases and related health problems, 10th Revision, Australian Modification (ICD-10-AM). First edition. Sydney: NCCH, 1998.
National Coding Centre. The Australian version of the International Classification of Diseases, 9th revision, clinical modification (ICD-9-CM). Sydney: University of Sydney, 1996.
University of Wollongong. Casemix and Coding Matters Newsletter available at http://nccc.uow.edu.au/productservices/casemixmatters/index.html
The International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) and the Australian Classification of Health Interventions (ACHI)
National Centre for Classification in Health, Australia;
| Description |
ICD-9-CM |
ACHI | Comments |
|---|---|---|---|
| Lower limb amputation with diabetes as co-morbidity | 84.1 with 250 in diagnosis codes 1-5 | 44370-00, 44367-00, 44367-02, 44361-00, 44361-01, 44358-00, 44364-00, 44364-01, 44338-00 in procedure code 1 with E10-E14 in diagnosis codes 1-5 | All records are included, NSW residents only, all ages. |
ICD-9-CM up to and including 1997-98
ACHI from 1998-99 onwards.
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Related Indicators
• In NSW in 2009, 9.4% of males and 7.0% of females aged 16 years and over reported having diabetes or high blood sugar. It is likely that there are many people with diabetes in NSW who are unaware they have it.
• Diabetes prevalence increases with age and socioeconomic disadvantage and is more prevalent among Aboriginal people and people born in the Mediterranean region.
• For people with diabetes, careful control of blood sugar levels through diet, exercise and in some cases medication and insulin injections, is vital to prevent complications. In NSW in 2006, around 60% of people with diabetes reported following a special diet, 43% reported taking tablets to manage their diabetes, around 11% required insulin injections and 8% reported ‘not doing anything’.
• While diabetes was the principal cause of just over 2% of all deaths in NSW in 2007, 2,435 or just over 5% of all deaths in that year were related to diabetes. Cardiovascular disease was the most common cause of death among people with diabetes.
• Hospitalisations for which diabetes was recorded as a principal diagnosis increased by more than 176% between 1990-91 and 2009-10. In July 2010 the Australian Coding Standard for diabetes was changed which resulted in around a 60% decrease in the number and rate of hospitalisation for diabetes as a principal diagnosis in NSW between 2009-10 and 2010-11.
• While Type 2 diabetes accounts for up to 90% of all diabetes cases in the community, it accounted for around 60% of all hospitalisations for diabetes in 2010-11. Type 1 diabetes accounted for around 35% of hospitalisations and gestational diabetes around 4%.
• The complications of diabetes include poor blood circulation and nerve function in the limbs, eye problems and kidney failure. There were 915 hospital admissions for lower extremity amputations in people with diabetes in 2010-11.
Diabetes definition and burden of disease
Diabetes mellitus is a group of closely related chronic conditions characterised by high blood sugar (glucose) levels. In uncontrolled diabetes, glucose builds up in the bloodstream and leads to a range of short- and long-term problems, including damage to vital organs.
Diabetes and its associated complications contribute significantly, both directly and indirectly, to mortality, morbidity, poor quality of life of sufferers and carers and the cost of health care. Experts agree that diabetes now represents one of the most challenging public health problems of the 21st century worldwide (Barr ELM et al. 2005). Diabetes and cardiovascular conditions together are the causes of about one-third of all years of life lost due to premature death and about one-fifth of all years lost to premature death or years lived with a disability in NSW. When the contribution of diabetes to stroke and heart disease was also included, diabetes contribution the total disease burden in Australia in 2003 rose from 5.5% to 8.3% (Begg et al. 2007).
Types of diabetes
There are three main forms of diabetes mellitus: Type 1 diabetes, Type 2 diabetes and gestational diabetes. Type 1 diabetes is estimated to be present in 10-15% of people with diabetes and is caused by a combination of genetic and environmental factors, but there are no known modifiable risk factors for this form of diabetes. Type 2 diabetes accounts for about 85-90% of all diabetes cases and primarily affects people older than 40 years. Several modifiable risk factors play a role in the onset of Type 2 diabetes, including obesity, physical inactivity and poor nutrition, as does genetic predisposition and ageing. Gestational diabetes mellitus occurs during pregnancy in about 3-8% of females not previously known to have diabetes. It is a temporary form of diabetes and usually resolves after the baby is born (Beers et al. 1999). The fourth, minor group, includes diabetes secondary to other conditions, for example diseases of the pancreas or drug-induced or chemical-induced diabetes.
Complications of diabetes
Diabetes can lead to acute and chronic complications. Acute metabolic disturbances can lead to coma. Chronic high blood glucose levels (hyperglycaemia) is associated with long-term damage, dysfunction and failure of virtually every body organ, especially the heart and blood vessels, eyes, kidneys and nerves. Consequently, diabetes predisposes those suffering from it to many severe conditions, including cardiovascular disease, as well as visual loss, amputations and renal failure.
Management of diabetes
Sustained, individualised management substantially reduces the risk of complications in people with diabetes. A combination of diet, exercise and medication (including insulin injections) is used and very frequent monitoring of blood glucose levels and other risk factors (for example blood lipids, blood pressure) is also required, as is regular screening for complications.
Explanations of nomenclature
In the past, Type 1 diabetes was called 'insulin-dependent diabetes mellitus' (IDDM) or 'juvenile-onset' and Type 2 diabetes was called 'non-insulin-dependent diabetes mellitus' (NIDDM). However, as insulin is often used to treat patients with Type 2 diabetes, the old terminology has been discouraged by the WHO since 2000 (NCCH Volume 5 2000).
Diabetes mellitus and diabetes insipidus are completely different conditions. Diabetes insipidus (DI, Central diabetes insipidus) is a temporary or chronic disorder that causes sufferers to excrete excessive quantities of otherwise normal urine and excessive thirst. Excessive urination and thirst are the features in common with diabetes mellitus , hence a Greek word for syphon (diabetes) is used in the name of both conditions. Diabetes insipidus is caused by deficiency of hormone called vasopressin (ADH) and is much less common than diabetes mellitus (Beers MH et al. 1999). This topic and data in the Report refer to the diabetes mellitus.
References
Barr ELM, Cameron A, Shaw JE, Zimmet PZ. The Australian diabetes, obesity and lifestyle study (AusDiab). Five year follow-up. Results for New South Wales. Melbourne: International Diabetes Institute, 2005.
Beers MH, Berkow R. The Merck manual of diagnosis and therapy. West Point: Merck & Co, 1999.
Begg S, Vos T, Barker B. The burden of disease and injury in Australia, 2003. Cat. no. PHE 82 edition. Canberra: AIHW, 2007. Available at http://www.aihw.gov.au/publications/index.cfm/title/10317
National Centre for Classification in Health. The International statistical classification of diseases and related health problems, 10th Revision, Australian Modification (ICD-10-AM). Volume 5. Sydney: NCCH, 2000.
The harm caused by diabetes can best be reduced by preventing the onset of Type 2 diabetes. Prevention through the modification of risk factors - particularly through lifestyle changes - is a goal of the National Diabetes Strategy (CDHAC 1999), which was endorsed in 1999 by all State and Commonwealth health ministers. This aim has also been emphasised in the National Service Improvement Framework for Diabetes (Australian Government Department of Health and Ageing 2006). Because Type 2 diabetes shares a number of risk factors with cardiovascular diseases the coordination of prevention strategies is essential to ensure consistent messages, pooling of resources, and better health outcomes. To that effect, the National Health Priority Council developed a National Chronic Disease Strategy (National Health Priority Action Council 2006) and a National Service Improvement Framework for Diabetes (Australian Government Department of Health and Ageing 2006). The NSW Ministry of Health is developing a population based chronic disease prevention strategy and has included chronic diseases in the population health plan, Healthy People NSW: Improving the Health of the Population (Population Health Division 2007).
Potentially preventable hospitalisations for chronic conditions
The most common chronic conditions defined as potentially preventable hospitalisations or ambulatory care sensitive hospitalisations are included in the NSW Severe Chronic Disease Management Program.
In response to the Garling Report 2008, the NSW Ministry of Health is implementing the NSW Severe Chronic Disease Management Program. This program is being overseen by the Chronic Disease Management Office to improve the quality of life of older people with chronic and complex conditions, their carers and families and to prevent unplanned and avoidable hospital admissions. It achieves this by coordinating a statewide chronic disease management approach.
The NSW Severe Chronic Diseases Management Program is focused on five major chronic diseases of interest that are recognised as having a major impact on the burden of disease in NSW. Furthermore, these conditions have been demonstrated to have improved outcomes through CDM approaches. The diseases of interest are Chronic Obstructive Pulmonary Disease (mainly emphysema and chronic bronchitis); Coronary Artery Disease (also known as coronary or ischaemic heart disease); Diabetes; Hypertension (high blood pressure); and Congestive Heart Failure.
People who are diagnosed with these diseases and who are experiencing repeated episodes in hospital are offered enrolment to the program. In the future the program will expand and be offered to people with these conditions even if they are not being admitted to hospital frequently to prevent their deterioration.
Interventions about diabetes in Aboriginal community
The NSW Chronic Care for Aboriginal People program worked in collaboration with Area Health Services and Aboriginal Community Controlled Health Services to prevent and manage conditions including diabetes, heart disease, stroke, hypertension and kidney disease among Aboriginal people. These conditions share common risk factors, and common approaches are needed to address them in Aboriginal communities (NSW Department of Health Vascular program 2004). This work will continue via Local Hospital Networks.
References
Commonwealth Department of Health and Aged Care. National Diabetes Strategy, 2000-2004. Canberra: CDHAC, 1999. Available at http://www.health.gov.au/internet/main/publishing.nsf/content/pq-diabetes-pubs-strat
National Health Priority Action Council. National Chronic Disease Strategy. Canberra: Australian Government Department of Health and Ageing, 2006a. Available at http://www.health.gov.au/internet/main/publishing.nsf/Content/pq-ncds
National Health Priority Action Council. National service improvement framework for diabetes. Canberra: Australian Government Department of Health and Ageing, 2006b. Available at http://www.health.gov.au/internet/main/publishing.nsf/Content/pq-ncds-diabetes
Population Health Division. Healthy people NSW. Improving the health of the population. Sydney: NSW Department of Health, 2007. Available at http://www.health.nsw.gov.au/pubs/2007/pdf/healthy_people.pdf
NSW Premier's Department. A new direction for NSW. State Plan. Sydney: NSW Premier's Department, 2006. Available at http://www.nsw.gov.au/stateplan/index.aspx?id=8f782cbd-0528-4077-9f40-75af9e4cc3e5
Useful websites include:
Diabetes Australia at http://www.diabetesaustralia.com.au/
Australian Bureau of Statistics at http://www.abs.gov.au
Australian Institute of Health and Welfare and its National Centre for Monitoring Diabetes. Available at http://www.aihw.gov.au
Australian Diabetes Society and its National Association of Diabetes Centres. Available at http://www.diabetessociety.com.au/nadc.asp
HealthInsite at http://www.healthinsite.gov.au
• Hospital separations have increased by more than 47% over the last twenty years but less than 14% over the last 10 years.
• Hospitalisation rates are consistently higher in females, but the gap is narrowing. In 2009-10 the most common causes of hospital separations were: factors influencing health (dialysis), factors influencing health (other than dialysis), injury and poisoning, digestive system diseases and maternal conditions.
Definition
The term 'hospitalisation' refers to a period of time during which a person stayed in a hospital for a defined purpose, which could be diagnostic, curative or palliative. A hospital stay starts with a formal process of admission and ends with a formal separation.
Hospitalisations are described in hospital statistics, which measure hospital activity. The number of patients in a period of time, number of beds, types of beds (for acute or chronic cases etc) and bed occupancy levels are measured among other variables. These statistics are compared to staffing levels, available funds and population size and are used to monitor the distribution and utilisation of hospital services. Hospitalisations can also be analysed by a patient's demographic and clinical characteristics such as their age and their clincial diagnosis.
In this report hospitalisations are analysed on the basis of separations ie the date the person completed that hospital episode, rather than the date that person was admitted into that hospital episode. The reason for this is that the coding of a patient's clinical diagnosis during a hospitalisation is done after separating from that hospital. This diagnosis may be different from the reason the person was admitted. Expert medical coders decide on the principal and associated diagnoses after separation based on the whole medical records of the patient.
Hospitalisation in NSW and in Australia
In NSW, the hospitalisation rate was 34,244 hospitalisations per 100,000 population in 2009-10. There were 2,571,687 hospitalisations in NSW in 2009-10, with 1,219,848 men and 1,351,824 women hospitalised in that financial year.
Rates of hospital separations are influenced by the age structure of the population, the incidence of acute disease and injury in the population, availability of health services, and availability of treatment options for diseases and injuries outside hospitals.
The Australian Institute of Health and Welfare report on hospitalisations in an annual publication: Australian hospital statistics. The number of hospitalisations in the whole of Australia was reported as 8,535,000 in 2009-10. The overall number of hospitalisations in NSW reported by the AIHW was 2,508,000 (very close to the figure published in this report) (AIHW Health services series no. 40. Cat. no. HSE 107 2011). Please refer to the Methods tab for more information and a discussion of differences between data sources.
Hospitalisation rates internationally
Hospitalisation rates for all causes are high in Australia and in NSW when compared to other developed English speaking countries. The Organisation for Economic Development and Cooperation (OECD) publish ‘discharge’ (separation) numbers and rates for overnight stays in hospital for the member countries in annually updated statistical tables. The data are based on calendar years. The rate calculated for Australia for 2008 was 16,243 per 100,000 population. The second highest rate was New Zealand’s rate at 14,161 per 100,000, while the lowest rate from developed English speaking countries was in Canada at 8,403 hospitalisations per 100,000 population, with rates in United Kingdom and United States placed in between with 13,762 and 13,086 hospitalisations per 100,000 respectively in 2008 (OECD 2011).
Causes of hospitalisation in NSW by sex and age in 2009-10
The leading causes of all hospitalisations in NSW in 2009-10 were factors influencing health (almost 13% of all), dialysis (around 12.5%), injury and poisoning (almost 12%), digestive system diseases (around 9.5%), maternal and neonatal admissions (7.3%) and investigations for symptoms and abnormal findings (just over 6%). Hospitalisations for the most common causes of death: cardiovascular diseases and malignant neoplasms (that is cancers) were distant eight (at 5.3%) and thirteen (at 2%) respectively.
The results of analyses by sex reveal that the causes of hospitalisation for the majority of disease categories do not differ significantly between the sexes. Except for obvious differences in hospitalisations for maternal conditions, the greatest differences between sexes were in hospitalisations for dialysis (15.6% and 9.5% in males and females respectively), cardiovascular diseases (6.5% to 4.3%) and malignant neoplasms, that is cancers (4.6% to 3.2%).
References
Australian Institute of Health and Welfare. Australian hospital statistics 2009–10. Health services series no. 40. Cat. no. HSE 107. Canberra: AIHW, 2011. Available at http://www.aihw.gov.au/publication-detail/?id=10737418863.
Organisation for Economic Cooperation and Development. OECD Health Statistics (database). OECD. Last updated 2011. Available at URL password protected
Interventions aiming to reduce hospitalisation rates are embedded in strategies dealing with specific health issues or specific disadvantaged populations.
These strategies focus on reduction of prevalence of conditions in the community (prevention of conditions arising in the first place) or on reduction of hospitalisations for these conditions via two different methods. One method focuses on preventing worsening of conditions and managing these conditions via primary care system and thus preventing admission to hospital. The topic of Potentially Preventable Hospitalisations (Ambulatory Care Sensitive Conditions) contains a discussion of details concerning these conditions. The NSW Chronic Care Program covers many such conditions requiring hospitalisation.
The other approach reduces the burden of hospitalisations on the health system by reducing the number of beds required at any point in time. It is based on the concept of Out-of-Hospital Care, which includes Hospital Care at Home. NSW Department of Health delivers an increasing type and number of services in out of hospital environment (NSW Department of Health 2011).
References
NSW Department of Health. Out-of-Hospital Care. NSW Departement of Health. Cited on July 19, 2011. Available at http://www.health.nsw.gov.au/performance/macca.asp
Useful websites include:
NSW Department of Health. Hospitals. NSW Department of Health. Cited on July 19, 2011. Available at http://www.health.nsw.gov.au/hospitals/index.asp
NSW Department of Health. Out-of-Hospital Care. NSW Departement of Health. Cited on July 19, 2011. Available at http://www.health.nsw.gov.au/performance/macca.asp
NSW Department of Health. NSW Health Services Comparison Data Book 2008-09. NSW Department of Health. Cited on August 10, 2011. Available at http://www.health.nsw.gov.au/pubs/2010/yellowbook_09.html
Bureau of Health Information at http://www.bhi.nsw.gov.au/
Australian Bureau of Statistics at http://www.abs.gov.au
Australian Institute of Health and Welfare at http://www.aihw.gov.au
HealthInsite at http://www.healthinsite.gov.au