1301.0 - Year Book Australia, 2008  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 07/02/2008   
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Contents >> Health >> Chronic disease

CHRONIC DISEASE

Chronic illness is a growing problem in Australia as the population ages. Chronic diseases such as diabetes, heart disease, cancer and arthritis are associated with a high burden of disease and account for a high financial burden in Australia. The burden of disease and injury is a measurement of the time lost due to premature death along with years of healthy life lost due to disability. Cancer and cardiovascular disease accounted for 37% of the total burden of disease and injury in Australia in 2003, mortality from these diseases accounted for 80% of that burden. Mental disorders and neurological and sense disorders were the next leading causes of the burden of disease and injury, together accounting for a further 25% of the total burden. However, mortality from these disorders contributed little.

Conditions such as diabetes, heart disease, cancer and arthritis (including injuries which contribute to chronic disease) are National Health Priority Areas (NHPAs). Many of these diseases can be prevented or delayed by addressing lifestyle factors such as poor diet or insufficient exercise, or by better management of conditions such as high blood pressure or obesity. There are a range of initiatives in place to prevent and manage chronic disease and reduce its impact.

Table 11.12 shows health expenditure on seven NHPAs. In total, expenditure on NHPAs in 2000-01 accounted for $22.3 billion (b), that is 44% of allocated recurrent expenditure or 36% of total health expenditure for the year. Hospital expenditure accounted for 48% of all expenditure on NHPAs.

11.12 HEALTH EXPENDITURE ON NATIONAL HEALTH PRIORITY AREAS(a) - 2000-01

Hospital
Aged care
homes
(b)
Out-of-
hospital
medical
services
Other
professional
services
(c)
Pharmaceuticals
Research
Total(d)
Disease group
$m
$m
$m
$m
$m
$m
$m

Cardiovascular diseases
2 533
526
782
73
1 411
153
5 479
Arthritis and other
musculoskeletal conditions
1 828
482
879
710
680
55
4 634
Injuries
2 831
105
622
265
184
6
4 013
Mental disorders
1 196
366
499
134
616
109
3 741
Cancer
1 988
37
343
22
183
215
2 918
Diabetes mellitus
289
38
183
33
234
35
812
Asthma
170
16
110
21
370
6
692
All NHPAs
10 835
1 570
3 418
1 258
3 678
580
22 289

(a) Allocated recurrent expenditure (which totalled $50.1b in 2000-01).
(b) Includes expenditure on residents that require and receive a level of care that falls within one of the four highest levels in residential aged-care services.
(c) Includes services delivered outside of hospitals by paramedical professionals such as physiotherapists, chiropractors, occupational therapists, audiologists, speech therapists, hydropaths, podiatrists, therapeutic and clinical massage therapists, clinical psychologists, dieticians and osteopaths.
(d) Includes other minor categories of expenditure.
Source: Australian Institute of Health and Welfare, 'Health system expenditure on disease and injury in Australia 2000-2001', Cat. No. HWE 28, AIHW, Canberra.


Cardiovascular disease

Cardiovascular disease, also known as 'circulatory disease', comprises all diseases and conditions involving the heart and blood vessels including high blood pressure, heart disease, stroke, and peripheral vascular diseases. Although the death rates from cardiovascular disease in Australia have notably decreased over the last three decades, this group of diseases remains as one of the leading causes of death in Australia.

In 2000-01, total health expenditure attributable to cardiovascular disease was $5.5b, which accounted for 10.9% of allocated recurrent health system expenditure (table 11.12).

Morbidity

The 2004-05 NHS indicated that around 3.5 million Australians (18%) reported having a circulatory system condition as a long-term condition (having lasted or being expected to last for six months or more). The most common cardiovascular condition reported was hypertension (high blood pressure) which affected 11% of the population.

The prevalence of long-term circulatory system conditions increases with age. For people aged 55 years and over, the prevalence of all circulatory system conditions is 46%. The prevalence of hypertension is 33%, and ischaemic heart disease (also called coronary heart disease) is 7%. The prevalence of cerebrovascular disease (stroke) is 2%.

Mortality

Despite declines in mortality rates in the last 30 years, cardiovascular disease (or diseases of the circulatory system) remains as one of the leading causes of death in Australia in 2005, accounting for 46,134 or 35% of all deaths. Ischaemic heart disease accounted for 18% of all deaths, and cerebrovascular diseases a further 9%.

Between 1995 and 2005, age-standardised death rates for diseases of the circulatory system declined by 41% for males (from 415 to 245 per 100,000 population), and 38% for females (from 282 to 175 per 100,000 population). In the same period age-standardised death rates for people declined from 341 to 208 per 100,000 population (graph 11.13).

11.13 Death rates for cardiovascular disease(a)
Graph: 11.13 Death rates for cardiovascular disease(a)


Arthritis and other musculoskeletal diseases

Osteoarthritis, rheumatoid arthritis and osteoporosis are the most commonly occurring musculoskeletal conditions. Although they are not immediately life threatening and have low associated mortality, they have substantial influence on the quality of life and impose a heavy economic burden on the community.

In 2000-01, total health expenditure attributable to musculoskeletal diseases was $4.6b, which accounted for 9.2% of allocated recurrent health system expenditure (table 11.12).

Osteoarthritis is one of the most common types of arthritis and affects the cartilage in the joints. Cartilage cushions the ends of bones where bones meet to form a joint. In osteoarthritis this cartilage degenerates. Osteoarthritis is most commonly found in the knees, neck, lower back, hip and fingers.

Rheumatoid arthritis is the most common form of inflammatory arthritis. Inflammatory arthritis is characterised by joint swelling and destruction. In rheumatoid arthritis the immune system attacks the tissues lining the joints. As a result of this attack, inflammation occurs causing pain, heat and swelling. The disease can also cause inflammation of connective tissue, blood vessels and organs.

Osteoporosis (porous bones) is a disease where bone density and structural quality deteriorate, leading to an increased risk of fracture. The most common sites of fracture are the bones of the spine, the hip and the wrist. However other bones are commonly affected, including the shoulder, ribs and the pelvis.

Morbidity

The 2004-05 NHS shows over 3 million Australians (15%) had some form of arthritis and over half a million Australians (3%) had osteoporosis. The prevalence is greater in females for all ages. The overall prevalence of arthritis is 18% for females compared with 13% for males, while the prevalence of osteoporosis is 5% for females and 1% for males. The prevalence of arthritis and osteoporosis was increasingly higher for older age groups in 2004-05 (graph 11.14). For people aged 65-74 years and 75 years and over, the prevalence of arthritis was 49% and 50% respectively, while the prevalence of osteoporosis was 12% and 17% respectively.

11.14 Prevalence of arthritis - 2004-05
Graph: 11.14 Prevalence of arthritis—2004–05


Injuries and deaths due to external causes

Injury and poisoning are broad terms that encompass the adverse effects on the human body that may result from events. These events may be accidental, such as falls, vehicle accidents and exposure to chemicals, or intentional such as suicide attempts and assaults by other people. Such events, and the factors involved in them, are collectively known as 'external causes of injury and poisoning', and are a significant source of preventable illness, disability and premature death in Australia.

Males and females, and people in different age groups, experience different levels and types of risk from injury events (risk in this sense refers to both the probability of an injury event occurring and the severity of the injuries that may result).

Morbidity

Respondents to the 2004-05 NHS were asked about events in the four weeks prior to interview that resulted in an injury for which they had sought medical treatment or taken some other action. Detailed information was collected about the most recent injury event in that period. Injuries data from the survey are presented in graph 11.15 and highlight differences in the reporting of injury events among males and females of different age groups.

11.15 Proportion who were recently injured(a) - 2004-05
Graph: 11.15 Proportion who were recently injured(a)—2004–05

During the 1990s, the number of people dying as a result of injury from traffic accidents decreased. However, traffic accidents remain a serious source of preventable death, injury and disability. Results from the 2004-05 NHS indicate two in 1,000 people experienced a recent injury as a result of a vehicle accident. Inexperienced road users are an acknowledged risk group in terms of the potential for death or injury from vehicle accidents. Results from the 2004-05 NHS show people aged 15-34 years experienced a higher rate of recent injury from vehicle accidents compared with people aged 35 years and over (graph 11.16).

11.16 Recently injured, by vehicle accident(a) - 2004-05
Graph: 11.16 Recently injured, by vehicle accident(a)—2004–05


Mortality

External causes were responsible for 8,015 deaths (6% of all deaths) registered in 2005 (table 11.17). Since 1995 there has been a 9% decrease in the standardised death rate for deaths from external causes of injury and poisoning. This decrease has been influenced largely by the decline in deaths from motor vehicle accidents.

In 2005, suicide and transport accidents accounted for nearly half (47%) of all deaths due to external causes. There were 2,101 deaths attributed to intentional self-harm (suicide) in 2005, accounting for 26% of the total deaths from external causes. Transport accidents accounted for 1,638 deaths, or 20% of total registered deaths in 2005 due to external causes. There was a much higher crude death rate for males than for females for both suicide (16.4 to 4.3 per 100,000) and transport accidents (12.1 to 4.1). The crude death rate for deaths resulting from falls was higher for females (5.1) than for males (4.6).

11.17 EXTERNAL CAUSES OF DEATH - 2005

Crude death rate(a)(b)(c)
Cause of death (ICD-10 code)
no.
%
Males(a)
Females(b)
Persons(c)

Suicide (intentional self-harm) (X60-X84)
2 101
26.2
16.4
4.3
10.3
Transport accidents (V01-V99)
1 638
20.4
12.1
4.1
8.1
Accidental poisoning by and exposure to noxious substances (X40-X49)
740
9.2
4.9
2.4
3.6
Falls (W00-W19)
996
12.4
4.6
5.1
4.9
Assault (X85-Y09)
199
2.5
1.3
0.7
1.0
Accidental drowning and submersion (W65-W74)
192
2.4
1.5
0.4
0.9
Other(d)
2 149
26.8
12.2
8.9
10.6
All external causes
8 015
100.0
53.0
25.9
39.4

(a) Per 100,000 males.
(b) Per 100,000 females.
(c) Per 100,000 population.
(d) Includes accidental exposure to other and unspecified factors (X58-X59), other accidental threats to breathing (W75-W84) as well as a variety of other external causes of death.
Source: ABS data available on request, Causes of Death collection.


Mental health

Most people in Australia enjoy good mental health. However, in 2004-05, approximately 2.1 million people (11% of the population) reported having a long-term mental or behavioural problem that had lasted, or was expected to last, for six months or more. Mental illness is not a major direct cause of death, but it is associated with a proportion of deaths due to suicide and some other conditions, and can lead to chronic disability. Mental ill health is one of the leading causes of non-fatal burden of disease and injury in Australia. Together, mental disorders accounted for 7.5% of allocated recurrent health system expenditure in 2000-01 (table 11.12).

Morbidity

In the 2004-05 NHS, information on long-term mental and behavioural problems was collected from all respondents. A long-term condition was defined as one which the respondent regarded as having lasted or was expecting to last six months or more. Respondents in the survey were not specifically asked if they had been diagnosed with any mental disorders, so the information they provided could be based on self-diagnosis rather than diagnosis by a health professional.

In 2004-05, 11% of the Australian population reported that they had a long-term mental or behavioural problem. Proportionally more females (11%) than males (10%) reported these problems. The most commonly reported problems for adults (aged 18 years and over) were classified into two groups - anxiety-related problems, and mood (affective) problems such as depression and bipolar disorder. Anxiety-related problems were reported by 4.4% of men and 7.0% of women. Mood (affective) problems were reported by 5.3% of men and 7.9% of women (graph 11.18).

11.18 Self-reported mental disorders(a) - 2004-05
Graph: 11.18 Self-reported mental disorders(a)—2004–05


The mental health of adults is also measured by asking about negative emotional states in the previous four weeks. In the 2004-05 NHS, using a scale of current psychological distress (Kessler 10 scale), a little under two-thirds (63%) of adults were classified to low levels of current psychological distress, 24% to moderate levels, 9% to high levels and 4% to very high levels.
Cancer

Cancer is a disease of the body's cells. Normally, cells grow and reproduce in an orderly manner. Sometimes, though, abnormal cells will grow. These abnormal cells may then reproduce and spread uncontrolled throughout the body. Cancer is the term used to describe about 100 different diseases including malignant tumours, leukaemia (a disorder of the white blood cells), sarcoma of the bones, Hodgkin's disease and non-Hodgkin's lymphoma (affecting the lymph nodes) in which uncontrolled cell growth threatens the rest of the body. Cancer is a major cause of death in Australia and accounted for 5.8% of allocated recurrent health system expenditure in 2000-01 (table 11.12).

Morbidity

In the 2004-05 NHS, an estimated 338,300 Australians (1.7%) reported they currently had a malignant neoplasm.

According to the AIHW and the Australasian Association of Cancer Registries there were 93,194 registered new cancer cases in 2003 (table 11.19). Prostate cancer (13,526 cases) was the most common cancer followed by colorectal cancer (12,536). The next most common cancers in persons were breast cancer (11,889 cases), melanoma of the skin (9,524) and lung cancer (8,249). Together they accounted for 60% of all registerable new cancer cases in that year. Cancer occurs more commonly in males than females. At the incidence rates prevailing in 2003, it would be expected that one in three men, and one in four women would be diagnosed with a malignant cancer before the age of 75 years.

Mortality

In 2005 malignant neoplasms (cancer) accounted for 37,975 deaths (excluding deaths from non-melanocytic skin cancer), or 29% of all deaths registered (table 11.19). Of these, there were 21,333 male deaths and 16,642 female deaths. Overall, cancer of the trachea, bronchus and lung was the leading cause of cancer deaths, accounting for 19% of all cancer deaths.

There were some differences in cancer death rates between males and females. Among males, the leading causes of cancer deaths were cancer of the trachea, bronchus and lung (22% of all male cancer deaths), prostate cancer (14%) and colon cancer (7%). Among females the leading causes of cancer deaths were breast cancer (16% of all female cancer deaths), cancer of the trachea, bronchus and lung (16%) and colon cancer (7%). Age-specific death rates for cancer increased markedly with age, and, in most age groups, were greater for males than for females.

Mortality is influenced by the number of new cases of cancer (incidence) and the length of time lived after the initial diagnosis of cancer is made (survival). Relative survival is a measure that takes into consideration the crude survival (time between diagnosis and death) in the cancer population, and the corresponding expected survival in the general population. Expressed as a percentage, it is the cancer population that survives a specific number of years after the diagnosis divided by the general population that survives the same number of years.In the general population during 1992-97, the expected proportion of males aged 60-69 years who survive for the next five years was 91%. The observed survival rate during 1992-97 after five years for males diagnosed with lung cancer at age 60-69 years is 11%. The five-year relative survival proportion for males diagnosed with lung cancer at age 60-69 years is the ratio of these two percentages, that is 12%.

By convention, the proportion of people surviving is measured at one, five and ten years after diagnosis. The periods reflect different stages of management during the life of a person diagnosed. For instance, the proportion of people surviving after one year can be a measure of the success of the interventions on the immediately detectable cancer, whereas five-year and ten-year measurements are strong indicators for remission or cure.

During 1992-97 the five-year relative survival proportions for all cancers for females (63%) were higher than those for males (57%) (table 11.19). Australian five-year relative survival proportions for all cancers was ranked second behind the United States of America for both males and females when compared with other western countries for which relative survival data are available.

11.19 DEATHS, INCIDENCE AND SURVIVAL RATES FOR COMMON REGISTRABLE CANCERS

Deaths (2005)
Incidence (2003)
Five-year relative survival (1992-97)
Males
Females
Males
Females
Males
Females
Cancer site
no.
no.
no.
no.
%
%

Stomach
699
391
1 216
657
22.6
24.8
Colon
1 395
1 242
4 185
3 959
58.3
58.7
Rectum
(a)907
(a)569
(a)2 672
(a)1 720
56.6
60.6
Pancreas
963
1 055
1 047
949
5.4
5.2
Lung(b)
4 694
2 705
5 281
2 968
11.0
14.0
Skin (melanoma)
862
411
5 535
3 989
90.0
94.6
Breast
17
2 719
101
11 788
-
84.0
Uterus
-
350
-
1 698
-
81.4
Cervix
-
216
-
725
-
74.6
Ovary
-
884
-
1 084
-
42.0
Prostate
2 946
-
13 526
-
82.7
-
Testis
21
-
638
-
95.4
-
Bladder
653
252
1 649
580
70.8
64.7
Kidney
(c)548
(c)375
(c)1 364
(c)768
59.9
57.5
Brain
611
437
770
590
23.8
23.8
Thyroid
33
53
361
1 041
87.9
95.6
Unknown primary
1 785
1 593
1 749
1 705
13.4
11.4
Hodgkin's Disease
35
29
247
183
82.6
84.4
Non-Hodgkin's Lymphoma
725
665
2 050
1 649
54.6
55.8
Leukaemia
800
614
1 460
1 064
41.2
43.2
All cancers(d)
21 333
16 642
51 418
41 776
56.8
63.4

- nil or rounded to zero (including null cells)
(a) Excluding anus and anal canal.
(b) Including trachea and bronchus.
(c) Including ureter and urethra, but excluding renal pelvis.
(d) Excluding non-melanocytic skin cancer.
Source: ABS data available on request, Causes of Death collection; Australian Institute of Health and Welfare, 'Cancer Survival in Australia: Part 1', Cat. No. CAN 13; Australian Institute of Health and Welfare, 'Cancer age-specific data cube', last viewed July 2007, <http://www.aihw.gov.au>.


Diabetes mellitus

Diabetes mellitus is a long-term condition characterised by high blood glucose (a type of sugar) level, which results from either the body producing little or no insulin, or the body not using the insulin properly (insulin resistance). Insulin is a hormone produced by the pancreas that helps the body cells use glucose.

There are three major types of diabetes mellitus. Type 1 diabetes is marked by extremely low levels of insulin. Type 2 diabetes is marked by reduced levels of insulin, or the inability of the body to use insulin properly. Gestational diabetes (which occurs in about 3-8% of pregnancies of women who have not been previously diagnosed with diabetes) is not usually long term. However, for women diagnosed with gestational diabetes, there is an increased risk of developing Type 2 diabetes later in life.

Diabetes is a costly disease, associated with substantial morbidity and mortality, primarily from cardiovascular complications, eye and kidney diseases, and limb amputations. In 2000-01, total health expenditure attributable to diabetes was $0.8b, accounting for 1.6% of allocated recurrent health system expenditure (table 11.12).

Morbidity

Results from the 2004-05 NHS indicate approximately 700,000 Australians (around 3.5%) reported having diabetes as a long-term condition. Results from the three successive NHSs show diabetes is a growing health problem in Australia. The prevalence of diabetes has risen from 2.4% in 1995 to 3.0% in 2001, and to 3.5% in 2004-05 (after adjusting for changes in the age structure of the population over time).

People born in some overseas regions have a higher prevalence of diabetes than people born in Australia. This difference may be largely due to a combination of genetic, biological, behavioural and environmental risk factors. For example, in 2004-05, of people born overseas, rates of diabetes were highest for persons born in southern and central Asia (8.7%). By comparison, the rate of diabetes for persons born in Australia was 3.3%.

Mortality

In 2005 diabetes mellitus was the underlying cause of death in 3,529 deaths, 2.7% of all deaths registered. Of these, 1,775 deaths were males and 1,754 females. The age-standardised death rate due to diabetes was 16 per 100,000 people (19 per 100,000 for males and 13 per 100,000 for females).

In addition to deaths where diabetes was the underlying cause, there were a further 8,345 deaths in 2005 where diabetes was listed as an associated (or contributing) cause of death. When diabetes was recorded as the underlying cause of death, other conditions listed as associated causes included ischaemic heart disease (53%), cerebrovascular diseases (22%), renal failure (27%) and heart failure (20%).
Asthma

Asthma is a chronic inflammatory disorder of the lung's air passages which makes them narrow in response to various triggers. This leads to episodes of shortness of breath and wheezing. Asthma can begin at all ages, including the very young. The disease can start as a mild chronic cough and lead to mild or severe wheezing, and sometimes even to respiratory arrest.

Although asthma has low associated mortality, people with asthma can experience reduced quality of life and require a range of health services, from general practitioner care to emergency department visits or hospital in-patient care. It is one of the most frequent reasons for hospitalisation among children aged 0-9 years.

The management of asthma is an important public health issue because of the personal burden it places on those with asthma, often with onset in childhood, and the financial burden it places on the health system. In 2000-01, health expenditure on asthma accounted for $0.7b, which represented 1.4% of allocated recurrent health expenditure (table 11.12).

Morbidity

The prevalence of asthma in Australia is one of the highest in the world, with more than two million Australians (10%) reporting the disease in 2004-05. Asthma is more prevalent in young people than older age groups. For people under 25 years of age, the prevalence of asthma was 12%. Up to 14 years of age, asthma was more common among males than among females. In older age groups, however, asthma was more common among females than among males.

Mortality

Asthma was identified as the underlying cause of a very small number of deaths (108 males and 210 females), amounting to 0.2% of deaths registered in Australia in 2005. Most asthma deaths occur in older age groups. The most recent peak in asthma deaths occurred in 1989, and age-standardised death rates for asthma have generally declined since then. Changes in coding rules for ICD-10, which apply to deaths data from 1997 onwards, have resulted in substantially decreased recording of asthma as an underlying cause of death compared with previous years (see Causes of Death, Australia, 2003 (3303.0)). Consequently, graph 11.20 shows trends for 1997 onwards.

11.20 Death rates for asthma
Graph: 11.20 Death rates for asthma



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