Using ICD10 primary diagnosis data for hospital separations by 5-year age group, it is possible to characterise broad stages of major morbidity through significant stages of the life cycle. This is done in a series of charts that show age-specific separation rates for the Aboriginal population of the East Kimberley according to select ICD10 disease categories. The selection of disease categories is based on those shown to be most prevalent in Table 7.3. In considering these charts, certain customised age groups are worth bearing in mind from the point of view of impact planning. These include the infant and pre-schooling age group (0-4 years), the years of compulsory schooling age group (5-14 years), the years of school-to-work transition age group (15-24 years), the years of family formation and employment age group (25-44 years), the years of family dissolution age group (45-64 years), and an aged category of those over 65 years, although arguably this latter category could be set at a much earlier cut-off point given the evidence for premature ageing in the context of high levels of Aboriginal adult mortality and morbidity (Divarakan-Brown 1985).
Figure 7.4 shows the prevalence of infectious diseases in the East Kimberley by 5-year age group. Clearly, these are most prominent among infants, with a rapid drop-off in school years and among young adults, though with some rise again in middle age and older years. Among infants, by far the most common infectious diseases are intestinal, presenting mostly as gastroenteritis, followed by scabies. Among older people, bacterial and viral infections are the more common cause of hospitalisation.
Hypertensive diseases, ischaemic heart diseases, pulmonary heart diseases, heart failure, and cerebrovascular diseases are all common reasons for hospitalisation among Aboriginal residents of the East Kimberley. Manifestation of these diseases commences in the early 30s and rises steadily through middle ages to reach prominence at older ages (Figure 7.5). With relatively high rates of over 100 per 1,000 by age 40, diseases of the circulatory system are a primary contributor to the overall profile of high adult morbidity observed in the region.
Very high rates of hospitalisation of 400 per 1,000 due to respiratory disease are evident among infants (Figure 7.6). These range across the disease classification, but especially prominent among infants are acute upper respiratory infections, influenza, pneumonia and asthma. As with diseases of the circulatory system, those of the respiratory system increase in prevalence in middle age over 35 years reaching a plateau of relatively high rates over 200 per 1,000 among the over 50s.
Hospital separations for digestive diseases, which often reflect poor nutrition, are relatively absent among infants and youth, but rise suddenly in the late 20s age group and remain at a fairly steady rate thereafter at around 90 per 1,000 (Figure 7.7). Prominent diagnoses include diseases related to dental problems (especially at younger ages), gastritis, and diseases of the gallbladder and pancreas. Interestingly, diseases of the liver represent only a minor share of hospital diagnoses.
Skin infections such as impetigo and abscesses are diagnosed relatively frequently among infants, although rates fall through the teen years (Figure 7.8). However, hospitalisation rates rise again through the young adult ages to plateau at around 80 per 1,000 among those aged between 30 and 50 years, before a further increase among the over 50s. Of interest is a rise in the incidence of cellulitis with increasing age, for which one known risk factor is diabetes.
Hospitalisation for reasons of injury and poisoning is very much a feature of young adult to middle age groups, with relatively low rates among children and older people (Figure 7.9). Despite this age variation, however, the primary diagnoses are reasonably similar across all ages and mostly involve injuries, wounds, fractures, and burns to various parts of the anatomy, along with complications of trauma and surgical and medical care. From Table 7.8, it is apparent that road injuries, falls, and assaults contribute substantially to this particular morbidity profile.
Among separations due to factors influencing health status and contact with health services, the need for regular attendance at regional centres for renal dialysis is a major factor leading to very high separation rates. As shown in Figure 7.10, dialysis separation rates commence rising at a relatively early age between 15 and 19 years and despite considerable fluctuation from one age group to the next, the trend line displays a general increase with age, with the rate of increase peaking around the mid 30s by which time separation rates are typically in excess of 300 per 1,000 due to the need for repeated treatment.
