Hospitalisation

Hospitalisation

Statistics on hospitalisation provide some insights into ill-health in the population [1]. They are, however, a fairly poor reflection of the extent and patterns of treatable illness in the community because they only represent illness that is serious enough to require hospitalisation and are influenced to some degree by the geographic accessibility of hospitals and variations in admission policies.

Another limitation of the available hospital statistics as an indicator of the health of the population is that they relate to episodes of hospitalisation rather than to individual patients [1]. Thus, multiple admissions by a relatively small number of patients – as occurs for renal dialysis, for example – limit the inferences that can be drawn about overall health patterns from aggregated statistics. These statistics are, of course, useful in assessing the need for health services, but of far less use in assessing health.

As is the case with other major health-related data collections (such as births and deaths), the identification of Indigenous status in hospital data collections is incomplete. An audit conducted by the AIHW in 2007-2008 found that NSW, Vic, Qld, WA, SA and the NT had adequate identification of Indigenous status, defined as 20% or less under-identification [2].

Separation rates5

Of the 8.2 million hospital separations for NSW, Vic, Qld, WA, SA and the NT6 during 2010-11, 327,435 (4.0%) were identified as Indigenous (Table 11) [3]. Around two-fifths (39%) of separations for Indigenous patients were for overnight stays.

In 2010-11, the overall age-standardised separation rate of 911 per 1,000 for Indigenous people was 2.5 times that for non-Indigenous people (Table 11) [3]. The age-standardised separation rate for Indigenous people living in the NT was 1,704 per 1,000, 7.9 times the rate for non-Indigenous people. About 80% of the difference between these rates was due to higher separations for Indigenous people admitted for renal dialysis.

Table 11: Numbers of hospital separations and age-standardised separation rates, by Indigenous status and jurisdiction, and Indigenous:non-Indigenous rate ratios, NSW, Vic, Qld, WA, SA and the NT, 2010-11

Jurisdiction	Indigenous		Non-Indigenous		Rate ratio
	Number	Rate	Number	Rate
Source: AIHW, 2012 [3]
Notes: Rates per 1,000 population Non-Indigenous rates and numbers include separations for which Indigenous status was not stated Rate ratio is the Indigenous rate divided by the non-Indigenous rate Numbers and rates for the NT are for public hospitals only The incomplete identification of Indigenous status means that these figures probably under-estimate the true difference between Indigenous and non-Indigenous rates
NSW	64,270	559	2,530,421	336	1.7
Vic	19,112	772	2,352,399	406	1.9
Qld	81,754	806	1,741,797	388	2.1
WA	67,944	1,440	898,089	397	3.6
SA	21,435	1,097	652,000	364	3.0
NT	72,920	1,704	31,513	216	7.9
All jurisdictions	327,435	911	8,206,220	367	2.5

Age-specific separation rates

Hospital separation rates were higher for Indigenous people living in NSW, Vic, Qld, WA, SA and the NT in 2010-11 than for their non-Indigenous counterparts for all age-groups, with the highest ratios in the middle adult years (Table 12) [3].

Table 12: Age-specific hospital separation rates, by sex and Indigenous status, and Indigenous:non-Indigenous rate ratios, NSW, Vic, Qld, WA, SA and the NT, 2010-11

Age-group (years)	Males			Females
	Indigenous rate	Non-Indigenous rate	Rate ratio	Indigenous rate	Non-Indigenous rate	Rate ratio
Source: Derived from AIHW, 2012 [3], ABS, 2009 [4], ABS, 2012 [5]
Notes: Non-Indigenous includes separations for which Indigenous status was not stated Rates are expressed as separations per 1,000 population Rate ratio is the Indigenous rate divided by the non-Indigenous rate The rates have not been adjusted for likely under-identification of Indigenous separations, so it is likely that the Indigenous rates, and hence the rate ratios, could be 25-30% higher
0-4	340	245	1.4	275	187	1.5
5-9	132	102	1.3	104	80	1.3
10-14	106	84	1.3	91	71	1.3
15-19	143	128	1.1	295	174	1.7
20-24	200	129	1.5	492	249	2.0
25-29	265	132	2.0	556	314	1.8
30-34	365	155	2.4	628	380	1.7
35-39	634	189	3.4	751	354	2.1
40-44	906	228	4.0	890	305	2.9
45-49	1,161	279	4.2	1,264	311	4.1
50-54	1,413	363	3.9	1,424	373	3.8
55-59	1,631	480	3.4	2,015	439	4.6
60-64	2,001	661	3.0	2,169	544	4.0
65+	1,947	1,288	1.5	2,083	943	2.2

Causes of hospitalisation

In 2010-11, the most common reason for the hospitalisation of Indigenous people living in NSW, Vic, Qld, WA, SA and the NT was for the care involving dialysis, which was responsible for 44% of Indigenous separations (143,306 separations) [6]. Many of these separations involved repeat admissions for the same people, some on an almost daily basis. The ICD 'Injury, poisoning and certain other consequences of external causes' (including motor vehicle accidents, assaults, self-inflicted harm, and falls) was the next most common cause of hospitalisation for Indigenous people, being responsible for 24,365 separations (7.4% of all separations, and 13% of separations excluding those for dialysis).

Excluding separations for dialysis and pregnancy-related conditions (most of which involved normal deliveries), the next leading causes of hospitalisation for Indigenous people in 2010-11 were respiratory conditions (responsible for 19,471 separations – 11% of separations excluding those for dialysis) and digestive diseases (16,647 separations – 9.0% of separations excluding those for dialysis) (Table 13) [6].

In 2010-11, Indigenous people were hospitalised at higher rates than non-Indigenous Australians for all major causes except for cancer and diseases of the musculoskeletal system and connective tissue [6].

Table 13: Numbers and proportions for leading causes of Indigenous hospital separations (excluding dialysis), and Indigenous:non-Indigenous rate ratios, NSW, Vic, Qld, WA, SA and the NT, 2010-11

Principal diagnosis	Number of separations	Proportion of separations (excluding dialysis) (%)	Rate ratio
Source: AIHW, 2012 [3], AIHW, 2012 [6]
Notes: Excludes hospitalisation for dialysis Numbers and rates for the NT are for public hospitals only Ratios are the standardised separation rates for Indigenous people divided by the standardised separation rates for non-Indigenous people (non-Indigenous includes separations for which Indigenous status was not stated) Due to the incomplete identification of Indigenous status, these figures probably under-estimate the true difference between Indigenous and non-Indigenous rates
Injury	24,365	13	2.0
Pregnancy-related	20,524	11	1.6
Respiratory diseases	19,471	11	2.8
Digestive diseases	16,647	9.0	1.1
Symptoms, signs and abnormal clinical and laboratory findings	15,470	8.4	1.5
Mental and behavioural disorders	13,824	7.5	2.1
Circulatory diseases	9,817	5.3	1.6
Genitourinary diseases	8,618	4.7	1.3
Diseases of the skin and subcutaneous tissue	7,730	4.2	2.5
Musculoskeletal system and connective tissue diseases	5,956	3.2	0.8
Infectious/parasitic diseases	5,742	3.1	2.0
Cancers	4,689	2.5	0.7
All causes, excluding dialysis	184,129	100	1.3

References

1. Thomson N, Ali M (2003) Births, deaths, and hospitalisation. In: Thomson N, ed. The health of Indigenous Australians. South Melbourne: Oxford University Press: 44-74
2. Australian Institute of Health and Welfare (2010) Indigenous identification in hospital separations data-quality report. Canberra: Australian Institute of Health and Welfare
3. Australian Institute of Health and Welfare (2012) Australian hospital statistics 2010-11. Canberra: Australian Institute of Health and Welfare
4. Australian Bureau of Statistics (2009) Experimental estimates and projections, Aboriginal and Torres Strait Islander Australians 1991 to 2021. Canberra: Australian Bureau of Statistics
5. Australian Bureau of Statistics (2012) Australian demographic statistics, September quarter 2011. Canberra: Australian Bureau of Statistics
6. Australian Institute of Health and Welfare (2012) Australian hospital statistics 2010-11 supplementary tables. Canberra: Australian Institute of Health and Welfare
7. Australian Institute of Health and Welfare (2011) Australian hospital statistics 2009-10. Canberra: Australian Institute of Health and Welfare
8. Australian Institute of Health and Welfare (2011) Aboriginal and Torres Strait Islander health performance framework 2010: detailed analyses. Canberra: Australian Institute of Health and Welfare

Endnote

5. 'Separation' refers to an episode of admitted patient care, which can be either a patient's total stay in hospital, or part of a patient's stay in hospital that results in a change to the type of care (e.g. from acute care to rehabilitation) [7]. Hospital separations are more widely known as 'admissions', but can also be referred to as 'hospitalisations' [8][7].

6. All hospitalisation data for the NT include only public hospitals.

---