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Utilisation of health services by Aboriginal Australians with diabetes
Diabetes Research and Clinical Practice, 20 (1993) 231-239 0 1993 Elsevier Scientific Publishers Ireland Ltd. All rights
231 reserved. 0168-8227/93/%06.00
DIABET 00758
Utilisation of health services by Aboriginal Australians with diabetes Christine B. Phillips, Mahomed S. Pate1 and Yolanda Cabaron Department of Health and Community Services and Central Australian Aboriginal Congress, Alice Springs, Northern Territory, Austrulia
(Received 25 September 1992; revision accepted 16 February 1993)
Summary
Diabetes is a major public health problem for Aboriginal Australians. We wished to determine the extent and pattern of health service utilisation by Aboriginal people with diabetes in central Australia. Medical records of all Aboriginal people known to have diabetes (n = 374), identified by a previous study, were examined for attendance to health services in central Australia. All had non-insulin-dependent diabetes. Between January 1984 and December 1986, Aboriginal adults with diabetes were admitted to hospital on 694 occasions, accounting for 10.8% of adult Aboriginal admissions. The crude admission rates were 0.78 and 0.84 per diabetes-year for men and women, respectively. The age-adjusted relative risks for admission, compared with Aboriginal non-diabetic patients, were 2.93 (95% C.I., 2.62-3.26) for men and 2.46 (95% C.I., 2.28-2.66) for women. If admission for conditions associated with diabetes are excluded, the admission rates were similar for the two groups. Infection was the most common reason for attendance to a health service, representing 41.7% and 39.8% of male and female admissions, and 21.8% and 26.3% of male and female outpatient attendances. Aboriginal patients with diagnosed diabetes suffer high morbidity and contribute disproportionately to health system costs.
Key words: Aboriginal;
Diabetes;
Morbidity;
Health
Introduction Reports on health service utilisation by diabetic patients are rare, even in populations with high prevalences of the disease [ 1,2]. In Australia, nonCorrespondence
to: Dr.
M. Pate],
Communicable
Centre, Danvin, Northern Territory 0810, Australia.
Diseases
service; Utilisation
insulin-dependent diabetes affects between 8% and 19% of Aboriginal adults [3], yet there has been only one report on hospitalisation rates in this group [4]. Studies on health service utilisation by diabetic patients generally have drawn their study populations from hospital separation statistics, or from registers of insulin-treated patients [4- lo].
232
Aboriginal patients with diabetes are infrequently treated with insulin, and have a younger age distribution than the cohorts in these studies [l 11. As part of a study to quantify the impact of diabetes on Aboriginal people and on the health services in central Australia, we found that the prevalence of known diabetes for Aboriginal men and women over the age of 25, based on health service attendances, was 6.00/oand 9.7%, respectively [Ill. We have reported already the high rates of admission for bacterial infection in this cohort between 1984 and 1986 [12]. We now report the frequency of and reasons for health centre attendances and admissions to hospital over the same period.
Background In 1986, central Australia had an Aboriginal population of 9943, of whom 2655 males and 2987 females were 15 years and over [ 131. Two-thirds of the Aboriginal population lived in small rural communities, with populations varying from 50 to 1200 people, and one-third in the region’s only urban centre, Alice Springs. The Alice Springs Hospital is the only tertiary referral centre in the region. It has 176 beds, and its outpatient services include specialist medical, surgical, ophthalmology, cardiology, renal and diabetic clinics. Patients who require highly are transferred to specialised management Adelaide or Darwin, 1500 km away. The Northern Territory Department of Health and Community Services has clinics in 27 rural communities, staffed by resident nursing staff and/or Aboriginal health workers. District Medical Officers visit at periods varying from 3 days/week to 1 day/fortnight. Medical records of all patients living in rural areas are maintained by health staff at the local clinic and in Alice Springs. The latter provide an up-to-date centralised record of the medical history of each person in the rural community. Most Aboriginal residents in Alice Springs attend the Central Australian Aboriginal Congress Health Service for primary health care; less than 1% attend local private general practitioners.
Subjects and Methods Study population
Methods used to identify all Aboriginal people with diagnosed diabetes in central Australia have been described previously [ll]. In brief, records from the hospital, rural and urban health services, nursing homes and death registers were examined systematically to identify Aboriginal patients known to have diabetes who had attended a health service at least once between 1984 and 1986. The diagnosis was then validated by a review of the patient’s medical records at the hospital and/or health centre. Case ascertainment of patients known to have diabetes was over 95% for rural areas and higher for urban areas [ 111. Reference population
Central Australia was defined as the Alice Springs Health Region of the Northern Territory. Because of their geographical isolation from Alice Springs, and separate, individual administrative structures, four rural health centres with a total population of approximately 1100 (600 adults) were excluded from the study. Case definition
The diagnosis of diabetes followed World Health Organisation criteria: symptoms and/or signs of diabetes with hyperglycaemia equal to or exceeding 11.1 mmol/l [ 141.Aboriginality followed the Commonwealth of Australia definition, i.e. a person of Aboriginal descent who identifies as Aboriginal and is accepted as such by his or her community [ 131.An adult was defined as someone 15 years of age or older. Women with diabetes in pregnancy were not included in this study. Reason for admission to hospital or attendance to health services
The reason for admission to hospital was taken to be the principal disease or condition which led to admission, and was determined after scrutiny of the clinical notes. The following categories of admission were considered to be precipitated by or associated with diabetes: soft tissue infection, systemic infection, chronic renal disease manifested by consistently elevated serum urea ( > 7.5 mmol/l) and creatinine ( > 0.12 mmol/l) levels, ischaemic
233
heart disease (myocardial infarction, angina or congestive cardiac failure with ischaemic changes on electrocardiograph), cerebrovascular disease, proliferative vascular disease, peripheral retinopathy and cataracts. Ketoacidosis was defined by the clinical history, the presence of ketones in the urine, and a metabolic acidosis (pH < 7.30). The criteria for defining soft tissue or systemic infections have been described elsewhere [ 121. Outpatient attendances to the health services were classified as attendances for management or review of hyperglycaemia, soft tissue infection, systemic infection, hypertension, trauma, or attendance to specialist clinics. Attendances for any other condition were classified as ‘other reasons’. An infection was defined as a bacterial infection if it was diagnosed on clinical grounds and treated with antibiotics. A course of antibiotics prescribed to an outpatient was recorded as one course of treatment, whether or not the patient completed the course.
Australian Bureau of Statistics census for the hospital catchment area (n = 6334 adults) [ 131. The denominator excluded the number of patients in our cohort and residents of the four rural health centres not included in our study. The numerator for the non-diabetics was derived from hospital separation statistics. Detailed computerised information on separations was available only for 1985 and 1986. Since the number of patients and their age and sex distributions were similar for these 2 years, their mean value was taken as the best estimate of admissions for 1984. Statistical methods
We used the software program EpiInfo Version 5 for data manipulation and descriptive statistics [15]. The summary relative risk adjusted for age was calculated by the Mantel-Haenszel procedure as described by Rothman and Boice [ 161.
Results Data collection
Details on attendances were transcribed in a standardised manner for hospital admissions and outpatient and health centre attendances. Attendance details of rural patients recorded at the Rural Health office in Alice Springs were crossreferenced with records in 12 of the 27 rural clinics visited by one of us (CBP). Data analysis
To assess the extent of under-reporting of diabetes as the primary or secondary diagnosis on discharge from hospital, we compared the hospital’s computerised separation statistics (available only for 1986) with our study data. The year, but not month, of diagnosis of diabetes was recorded for all patients. To calculate the number of observed diabetes-years of patients diagnosed after January 1st 1984, we accorded June 30th as the date of diagnosis for the respective year. For the remaining patients, January 1st 1984 was the entry point. Either the day of death or 31st December 1986 in the survivors was taken as the end-point. Their admission rates were then compared with those for the non-diabetic adult Aboriginal population. The denominator was drawn from the 1986
One hundred thirty-eight men and 236 women known to have diabetes (male: female ratio, 1:1.7) attended health services in central Australia during the study period. All had non-insulindependent diabetes. Thirteen percent were prescribed insulin at some stage in the study period. A further 10 patients were known to have diabetes, but as they had attended a health service before but not during the study period, they were excluded from the study. Frequency of admission to hospital
Two hundred seventy-three of the 374 diabetic patients were admitted to Alice Springs Hospital on 694 occasions. The male to female ratio of patients admitted was also 1:1.7. The age and sex distributions, and the proportion they constitute of known diabetic patients, are shown in Fig. 1. Figure 2 shows the mean bed-days per diabetes-year by age group and sex. Of all adult Aboriginal patients admitted to hospital, patients with diabetes accounted for 10.0% and 11.2% of male and female admissions, respectively, and 12.9% and 14.7% of the total bed days. The hospital has 85 beds for adult medical, surgical and gynaecological patients of all races. On
40 r
30I
nales
10 1
Fig. 1. Age distribution
20 1
25-29 IS-19
20-24
of study population
and of patients
0 0 Number of patients
m
35-39 30-34
so-54 45-48 40-44
56-88
60-84
65-89
70-74
75-79
80*
Age Group (years)
admitted
10 3
to hospital
(H).
20 I
J
1
1
30 I
Pecbales
I I
---z
235 Mean bed days/diabetes-year 20 r ~- ~__---
25-34
35-44
45-54
55-64
85-74
‘74
Age group (years) Fig. 2. Mean bed-days per diabetes-year for men (m and women (U), distributed according to age.
any one day, 7 (8.2%) of these beds were occupied by an Aboriginal patient with diabetes. If admissions categorised as ‘other’ are excluded, 5 (5.9%) beds were occupied by Aboriginal patients admitted with conditions related to diabetes. The crude admission rates for men and women per diabetes-year were 0.78 and 0.84, respectively. The number of admissions by age group and sex, the diabetes-years of observation, and relative risks for admission of patients with diabetes are shown in Table 1. The crude relative risks for admission in both sexes did not change after adjusting for age. As there were only 5 admissions in the 15-24-year age group, this group has been excluded from the relative risk analysis. Reason for admission to hospital Table 2 shows the reasons for admission and duration of stay. If inpatient stays for ‘other’ categories (e.g. trauma, 67 admissions; cancer 10 admissions) are excluded, 217 patients (58% of 374) were admitted on 436 occasions (63% of 694) for a condition which could have been precipitated by or associated with diabetes. The crude admission rates of 0.26 and 0.33 per diabetes-year for men and women with ‘other’ conditions are almost identical to the expected rate. Overall, 6.5% of male admissions and 6.9% of Aboriginal Aboriginal female admissions were considered to be related to diabetes. The range, interquartile range and median age
by cause of admission is shown in Fig. 3. Bacterial infection was the most frequent reason for admission (42% and 40% of male and female admissions, respectively). Details on these patients have been published elsewhere [ 121. Of the 24 patients with renal disease (37 admissions), 5 males and 2 females had histologically confirmed diabetic nephropathy. All 7 had proliferative retinopathy as well. In the remaining 17 patients (26 admissions), the contribution of diabetes to renal disease was not known, as renal biopsies had not been performed. Four of the 19 patients admitted with ischaemic heart disease had acute myocardial infarctions, with diagnostic ECG and cardiac enzyme changes. Two of them died within 5 days of admission; neither had any history of angina. There were 7 admissions for acute metabolic complications. Five patients (3 on sulfonlyureas and 2 on insulin) were admitted on 6 occasions for hypoglycaemia. Symptoms included hemiparesis, generalised fitting, and loss of consciousness. All responded immediately to intravenous glucose. A 55-year-old woman with no past history of diabetes was admitted ketoacidosis for precipitated by E. coli septicaemia. Forty-six patients were managed in the intensive care unit for a total of 226 days. Over the 3-year period, 24 patients were transferred by air to Adelaide for more specialised medical care on 32 occasions, a rate of 4 transfers1100 diabetes-years. Of 65 emergency aeromedical evacuations of diabetic patients from rural areas, 42 were for acute infections. Twenty-nine diabetic patients died in hospital during the study period, accounting for 60% of deaths in our cohort. Of these, 13 deaths were due to infection, 5 due to terminal renal failure, and 3 due to strokes. Further details on the case fatality will be presented separately. Underenumeration of diabetes In 1986, 142 patients with diabetes were admitted to hospital according to our data, but only 101 patients had diabetes recorded as a primary or secondary diagnosis in the hospital’s computerised separation data. This yielded an underenumeration of 29%.
240
Total
306.44
25.40 90.75 87.52 42.15 47.13 13.49 0.26
0.24 0.29 0.27 0.26 0.23 0.56
Total
Soft tissue infection Systemic infection Control of glycaemia Renal disease Ischaemic heart disease Cerebrovascular disease Cataracts Other
Cause for admission
34 33 13 9 9 6 2 47 235
53 (22.6) 45 (19.1) 14 (6.0) 13 (5.5) 19 (8.1) 7 (3.0) 3 (1.3) 81 (34.5) 2799
849 636 87 71 148 93 33 882
Mean: 11.9
11.5 11.0 5.5 6.0 6.0 14.0 10.0
44 74 34 15 10 9 3 92
.
533.67
77.0 135.08 152.41 101.10 49.50 18.58
Diabetes years
459
66 (14.4) 117 (25.4) 40 (8.7) 24 (5.2) 17 (3.7) 14 (3.0) 4 (0.9) 177 (38.6)
No. of admissions (%)
n
n
Bed days
Women
Men No. of admissions (%)
449
56 105 109 120 44 15
Median stay (days)
2.92 (2.62-3.26)
2.74 (1.80-4.17) 2.44 (1.97-3.02) 2.61 (2.08-3.28) 3.79 (2.90-4.96) 4.38 (3.31-5.80) 1.20 (0.58-2.48)
Reason for admission to hospital and duration of inpatient stay
TABLE 2
aAdmission rate in adult Aboriginal non-diabetic population
17 64 61 42 47 9
Relative risk (95% CI)
No. of admissions
Expected admission ratea
No. of admissions
Diabetes years
Women
Men
25-34 35-44 45-54 55-64 65-74 >75
Age group (*years)
Age and sex specific diabetes-years of observation and relative risk of admission
TABLE 1
4787
723 1198 406 346 178 526 56 1354
Bed days
0.34
0.44 0.31 0.22 0.18 0.24 0.53
Expected admission ratea
Mean: 10.4
8.0 9.0 7.5 8.5 9.0 7.0 14.5
Median stay (days)
2.46 (2.28-2.66)
1.64 (1.34-2.01) 2.49 (2.1 l-2.94) 3.23 (2.68-3.89) 6.53 (5.42-7.86) 3.64 (2.76-4.80) 1.53 (1.02-2.30)
Relative risk (95% CI)
231
Women
Men
Soft tieeue
t
infection Systemic intection Renal
Control
I.H.D.
C.V.A.
0
IO
20
30
40
60
60
70
60
I
1
I
0
10
20
1
1
1
1
30
40
60
60
’
70
60
Age (years)
Age (years)
Fig. 3. Box plot showing the range, the interquartile range and the median age by cause of admission in men and women.
Outpatient attendances One hundred seventeen men and 215 women attended at least one of the health services as an outpatient in the study period (Table 3). Women TABLE 3 Reason for attendance to outpatient services Reason for attendance
Men n (%)
Women n (%)
Infection Urinary tract infection Respiratory tract infection Soft tissue infection Site uncertain Diabetes follow-up Specialist clinics Medical Eye Renal Other Trauma Hypertension Other
246 (21.8) 9 (0.8) 87 (7.7) 134 (11.9) 16 (1.4) 183 (16.3)
769 (26.3) 236 (8.1) 275 (9.4) 223 (7.6) 35 (1.2) 507 (17.3)
56 (5.0) 30 (2.7) 9 (0.8) 23 (2.0) 108 (9.6) 43 (3.8) 424 (37.8)
226 (7.7) 91 (3.3) 21 (0.7) 89 (3.0) 183 (6.2) 110 (3.7) 926 (31.6)
Total
1122 (100)
2928 (100)
attended health services more frequently than did men. If attendances to specialist referral clinics are excluded, infection accounted for 24.5% and 30.8% of all male and female self-directed presentations to health services (Table 3). Seventeen percent of attendances were for review or treatment of diabetes. Median age of attendance to outpatient services for different causes was similar to that described for hospital admissions, suggesting that the cohorts who were hospitalised did not represent an older subgroup. Over the 3-year period, 769 courses of antibiotics were prescribed to 236 patients, an average of 0.89 courses/diabetes-year.
Discussion
This study differs from many previous studies in that it reports the experience of a cohort of people with diagnosed non-insulin-dependent diabetes, the majority of whom were not treated with insulin. The only report of health service utilisation by
238
Aboriginal patients with diabetes used hospital separation data to compare their admission rates with those of non-Aboriginal patients with diabetes [4]. One drawback of this method is that diabetes frequently is under-recorded as the primary or subsidiary diagnosis at separation. A review at three hospitals in England reported that diabetes was not recorded at separation in 26% of diabetic admissions [ 171; in our study, this occurred in 29% of the admissions. An important limitation of our study is that the results refer only to patients with diagnosed diabetes. As the true prevalence of diabetes in central Australia is at least twice the prevalence of known diabetes [l I], the morbidity from diabetes has probably been exaggerated by our study design. It should also be noted that our study population was identified from health centre data. This is likely to over-represent known diabetic patients with more severe disease, who required regular medical attention. However, our review of all medical records and discussions with urban and rural health staff revealed only 10 patients with diagnosed diabetes who had not attended health services in the study period. Health centres are usually staffed by members of the local community. They have extensive knowledge of their own communities; it is unlikely that a patient with diagnosed diabetes would not have been identified for our study. These results therefore indicate that patients with diagnosed diabetes have severe disease which requires intensive medical care. While the prevalence of known diabetes above 15 years was 3.8% and 6.3% for men and women, respectively [ 111, patients with diabetes accounted for 10.8% of adult Aboriginal admissions to hospital, and 14.0% of hospital bed days. For conditions that are not related to diabetes, the admission rate was similar to that for non-diabetic Aboriginal adults. A less marked, but high admission rate was also reported in New Zealand, where patients with diagnosed diabetes accounted for 1.5% of adults in the community, but 2.2% of all hospital admissions [lo]. The age and sex specific admission rates of patients with diabetes were significantly higher than those for patients who did not have diabetes. The denominators in the latter group were drawn from Australian Bureau of Statistics census data, which
may have underestimated the Aboriginal population by up to 5% [18]. It is possible, therefore, that the relative risk for admission could be even higher than our estimates. Women attended outpatient services more frequently than men, although admission rates were similar. Attendance for routine check-up and education accounted for 17% of attendances. Some of these observations may reflect cultural perceptions of health and health service utilisation, and warrant further study. Bacterial infections were the major reason for admission and accounted for almost one-quarter of outpatient attendances. Few studies have related age distribution to cause of admission, and none have commented on bacterial infection. As expected, slightly older people were admitted with The relatively cardiovascular complications. young age of admission for bacterial infection (median age at admission for soft tissue infection: 45 years for women and 49 years for men) is of concern, and identifies a priority for secondary prevention of complications. The frequent prescription of antibiotics by Aboriginal health workers and nursing staff has generally been encouraged in the rural areas (unpublished observation). Doctors visit at weekly or fortnightly intervals, and specimens for laboratory testing have to be forwarded to Alice Springs, with attendant time delays. Under these circumstances, the generous prescription of antibiotics may have been effective in preventing more severe infections, thus reducing the need for urgent aerial evacuations. The practice reinforces the need to develop standard guidelines for antibiotic use, basing drug selection on common causative organisms and local sensitivity patterns. Ischaemic heart disease and strokes were not major reasons for admission to hospital in our study. The true frequency of these and other atherosclerotic complications requires a more comprehensive assessment. This need is underscored by the high prevalence of the associated risk factors, obesity, hyperinsulinaemia, hypertension and hypertriglyceridaemia in Aboriginal Australians [3]. Studies in the United States have shown that with better care in the community, many diabetic admissions are preventable [19,20]. In New South Wales, Australia, one hospital reduced by two-
239
thirds its hospital bed-occupancy rate for diabetic patients after improving its ambulatory care facilities [21]. A community-based diabetes education and control programme in Victoria reduced diabetes-specific admissions by 82% over 12 months [22]. In central Australia, if admissions for infection alone could be reduced by half, the overall admission of Aboriginal diabetic patients would decrease by 23%, a saving of 568 bed days per year. Our findings stress the need to review current methods of health service delivery to Aboriginal patients with diabetes. Since this study was completed, several community-based diabetes control programs have been established in central Australia. Long-term evaluation of these programs will indicate whether or not they have any effect on the morbidity and health service costs attributable to diabetes.
Acknowledgements
We are grateful to the management and staff of the Alice Springs Central Australian Aboriginal Congress, Hospital and rural health clinics in central Australia. We acknowledge the assistance of Jane O’Sullivan and the Medical Records Departments of Alice Springs Hospital and Royal Darwin Hospital. Dr David Thomas provided valuable suggestions for the manuscript. CBP was supported by a grant from the NH&MRC and by the AMA-AMSA J.G. Hunter Research Fellowship, and worked on the project, in part, towards a Bachelor of Medical Science thesis at the University of Melbourne.
References Zimmet, P. (1985) Deficient diabetes data. Med. J. Aust. 143, 431-432. Sicree, R.A., Ram, P. and Zimmet, P. et al. (1985) Mortality and health service utilization amongst Melanesian and Indian diabetics in Fiji. Diabetes Res. Clin. Pratt. I, 221-234. O’Dea, K. (1991) Westemisation, insulin resistance and diabetes in Australian Aborigines. Med. J. Aust. 155, 258-264. Taylor, R. and Reid, M. (1985) Admissions to hospital for diabetes in Aborigines and other Australians, rural NSW, 1977-78. Comm. Health Stud. 5(2), 142-146.
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Scott, R.S., Brown, L.J. and Clifford, P. (1985) Use of health services by diabetic persons II. Hospital admissions. Diabetes Care 8(l), 43-47. Williams, D.R.R. (1985) Hospital admissions of diabetic patients: information from Hospital Activity Analysis. Diabetic Med. 2, 27-32. Green, A. and Solander, F. (1984) Epidemiological studies of diabetes in Denmark: 6. Use of hospital services by insulin-treated diabetic patients. Diabetologia 26, 195-198. Sutton, L., Plant, A.J. and Lyle, D.M. (1990) Service and costs of hospitalisation for children and adolescents with insulin-dependent diabetes mellitus in N.S.W. Med. J. Aust. 152, 130-135. Fishbein, H.A., Faith, G.A. and Ellis, S.E. (1982) Incidence and hospitalisation patterns of insulin-dependent diabetes mellitus. Diabetes Care 5, 630-633. Brown, L.J., Scott, R.S. and Beaven, D.W. (1985) Utilisation of health services by diabetic persons III: audit of hospital admissions and bed occupancy. N.Z. Med. J. 98. 839-843. Phillips, C.B., Patel, M.S. and Cabaron, Y. (1990) Diabetes among Aboriginal people in central Australia: a high prevalence based on health service attendance. Med. J. Aust. 153, 314-318. Pate], M.S., Phillips, C.B., Cabaron, Y. (1991) Frequent hospital admissions for bacterial infections among Aboriginal people with diabetes in central Australia. Med. J. Aust. 155, 218-222. Australian Bureau of Statistics (1986). Census of the Northern Territory population. 1986. ABS, Canberra. World Health Organisation Study Group on Diabetes Mellitus (1985). Diabetes Mellitus. WHO, Geneva (WHO Tech. Rep. Ser. 727). Dean, Ag., Dean, J.A., Burton, A.H. and Dicker, R.C. (1990) EpiInfo Version 5: a word processing, database and statistics program for epidemiology and microcomputers. USD Incorporated, Stone Mountain, Georgia. Rothman, K.J. and Boice, J.D. (1979) Epidemiologic analysis with a programmable calculator. US Government Printing OffIce, Washington DC (NIH Publication 79- 1649). Williams, D.R.R., Fuller, J.H. and Stevens, L.K. (1989) Validity of routinely collected hospital admissions data on diabetes. Diabetic Med. 6, 320-324. Australian Bureau of Statistics (1989). Census 86: data quality. Aboriginal and Torres Strait Islander counts. ABS, Canberra (Catalogue No. 2602.0). Miller, L.V. and Goldstein, J. (1972) More efticient care of diabetic patients in a county-hospital setting. N. Engl. Med. J. 286, 1388-1391. Runyan, J.W. Jnr, Vander Zwaag. R., Joyner, J.B. and Miller, S.T. (1980) The Memphis diabetes continuing care program. Diabetes Care 3, 382-386. Roffltt, P., Fowler, J. and Eather, G. (1979) Bed occupancy by diabetic patients. Med. J. Aust. I, 244-245. Zimmet, P. (1987) The Diabetes Education and Control Program in Victoria and its evaluation. Trans. Menzies Foundation 13, 57-73.
231 reserved. 0168-8227/93/%06.00
DIABET 00758
Utilisation of health services by Aboriginal Australians with diabetes Christine B. Phillips, Mahomed S. Pate1 and Yolanda Cabaron Department of Health and Community Services and Central Australian Aboriginal Congress, Alice Springs, Northern Territory, Austrulia
(Received 25 September 1992; revision accepted 16 February 1993)
Summary
Diabetes is a major public health problem for Aboriginal Australians. We wished to determine the extent and pattern of health service utilisation by Aboriginal people with diabetes in central Australia. Medical records of all Aboriginal people known to have diabetes (n = 374), identified by a previous study, were examined for attendance to health services in central Australia. All had non-insulin-dependent diabetes. Between January 1984 and December 1986, Aboriginal adults with diabetes were admitted to hospital on 694 occasions, accounting for 10.8% of adult Aboriginal admissions. The crude admission rates were 0.78 and 0.84 per diabetes-year for men and women, respectively. The age-adjusted relative risks for admission, compared with Aboriginal non-diabetic patients, were 2.93 (95% C.I., 2.62-3.26) for men and 2.46 (95% C.I., 2.28-2.66) for women. If admission for conditions associated with diabetes are excluded, the admission rates were similar for the two groups. Infection was the most common reason for attendance to a health service, representing 41.7% and 39.8% of male and female admissions, and 21.8% and 26.3% of male and female outpatient attendances. Aboriginal patients with diagnosed diabetes suffer high morbidity and contribute disproportionately to health system costs.
Key words: Aboriginal;
Diabetes;
Morbidity;
Health
Introduction Reports on health service utilisation by diabetic patients are rare, even in populations with high prevalences of the disease [ 1,2]. In Australia, nonCorrespondence
to: Dr.
M. Pate],
Communicable
Centre, Danvin, Northern Territory 0810, Australia.
Diseases
service; Utilisation
insulin-dependent diabetes affects between 8% and 19% of Aboriginal adults [3], yet there has been only one report on hospitalisation rates in this group [4]. Studies on health service utilisation by diabetic patients generally have drawn their study populations from hospital separation statistics, or from registers of insulin-treated patients [4- lo].
232
Aboriginal patients with diabetes are infrequently treated with insulin, and have a younger age distribution than the cohorts in these studies [l 11. As part of a study to quantify the impact of diabetes on Aboriginal people and on the health services in central Australia, we found that the prevalence of known diabetes for Aboriginal men and women over the age of 25, based on health service attendances, was 6.00/oand 9.7%, respectively [Ill. We have reported already the high rates of admission for bacterial infection in this cohort between 1984 and 1986 [12]. We now report the frequency of and reasons for health centre attendances and admissions to hospital over the same period.
Background In 1986, central Australia had an Aboriginal population of 9943, of whom 2655 males and 2987 females were 15 years and over [ 131. Two-thirds of the Aboriginal population lived in small rural communities, with populations varying from 50 to 1200 people, and one-third in the region’s only urban centre, Alice Springs. The Alice Springs Hospital is the only tertiary referral centre in the region. It has 176 beds, and its outpatient services include specialist medical, surgical, ophthalmology, cardiology, renal and diabetic clinics. Patients who require highly are transferred to specialised management Adelaide or Darwin, 1500 km away. The Northern Territory Department of Health and Community Services has clinics in 27 rural communities, staffed by resident nursing staff and/or Aboriginal health workers. District Medical Officers visit at periods varying from 3 days/week to 1 day/fortnight. Medical records of all patients living in rural areas are maintained by health staff at the local clinic and in Alice Springs. The latter provide an up-to-date centralised record of the medical history of each person in the rural community. Most Aboriginal residents in Alice Springs attend the Central Australian Aboriginal Congress Health Service for primary health care; less than 1% attend local private general practitioners.
Subjects and Methods Study population
Methods used to identify all Aboriginal people with diagnosed diabetes in central Australia have been described previously [ll]. In brief, records from the hospital, rural and urban health services, nursing homes and death registers were examined systematically to identify Aboriginal patients known to have diabetes who had attended a health service at least once between 1984 and 1986. The diagnosis was then validated by a review of the patient’s medical records at the hospital and/or health centre. Case ascertainment of patients known to have diabetes was over 95% for rural areas and higher for urban areas [ 111. Reference population
Central Australia was defined as the Alice Springs Health Region of the Northern Territory. Because of their geographical isolation from Alice Springs, and separate, individual administrative structures, four rural health centres with a total population of approximately 1100 (600 adults) were excluded from the study. Case definition
The diagnosis of diabetes followed World Health Organisation criteria: symptoms and/or signs of diabetes with hyperglycaemia equal to or exceeding 11.1 mmol/l [ 141.Aboriginality followed the Commonwealth of Australia definition, i.e. a person of Aboriginal descent who identifies as Aboriginal and is accepted as such by his or her community [ 131.An adult was defined as someone 15 years of age or older. Women with diabetes in pregnancy were not included in this study. Reason for admission to hospital or attendance to health services
The reason for admission to hospital was taken to be the principal disease or condition which led to admission, and was determined after scrutiny of the clinical notes. The following categories of admission were considered to be precipitated by or associated with diabetes: soft tissue infection, systemic infection, chronic renal disease manifested by consistently elevated serum urea ( > 7.5 mmol/l) and creatinine ( > 0.12 mmol/l) levels, ischaemic
233
heart disease (myocardial infarction, angina or congestive cardiac failure with ischaemic changes on electrocardiograph), cerebrovascular disease, proliferative vascular disease, peripheral retinopathy and cataracts. Ketoacidosis was defined by the clinical history, the presence of ketones in the urine, and a metabolic acidosis (pH < 7.30). The criteria for defining soft tissue or systemic infections have been described elsewhere [ 121. Outpatient attendances to the health services were classified as attendances for management or review of hyperglycaemia, soft tissue infection, systemic infection, hypertension, trauma, or attendance to specialist clinics. Attendances for any other condition were classified as ‘other reasons’. An infection was defined as a bacterial infection if it was diagnosed on clinical grounds and treated with antibiotics. A course of antibiotics prescribed to an outpatient was recorded as one course of treatment, whether or not the patient completed the course.
Australian Bureau of Statistics census for the hospital catchment area (n = 6334 adults) [ 131. The denominator excluded the number of patients in our cohort and residents of the four rural health centres not included in our study. The numerator for the non-diabetics was derived from hospital separation statistics. Detailed computerised information on separations was available only for 1985 and 1986. Since the number of patients and their age and sex distributions were similar for these 2 years, their mean value was taken as the best estimate of admissions for 1984. Statistical methods
We used the software program EpiInfo Version 5 for data manipulation and descriptive statistics [15]. The summary relative risk adjusted for age was calculated by the Mantel-Haenszel procedure as described by Rothman and Boice [ 161.
Results Data collection
Details on attendances were transcribed in a standardised manner for hospital admissions and outpatient and health centre attendances. Attendance details of rural patients recorded at the Rural Health office in Alice Springs were crossreferenced with records in 12 of the 27 rural clinics visited by one of us (CBP). Data analysis
To assess the extent of under-reporting of diabetes as the primary or secondary diagnosis on discharge from hospital, we compared the hospital’s computerised separation statistics (available only for 1986) with our study data. The year, but not month, of diagnosis of diabetes was recorded for all patients. To calculate the number of observed diabetes-years of patients diagnosed after January 1st 1984, we accorded June 30th as the date of diagnosis for the respective year. For the remaining patients, January 1st 1984 was the entry point. Either the day of death or 31st December 1986 in the survivors was taken as the end-point. Their admission rates were then compared with those for the non-diabetic adult Aboriginal population. The denominator was drawn from the 1986
One hundred thirty-eight men and 236 women known to have diabetes (male: female ratio, 1:1.7) attended health services in central Australia during the study period. All had non-insulindependent diabetes. Thirteen percent were prescribed insulin at some stage in the study period. A further 10 patients were known to have diabetes, but as they had attended a health service before but not during the study period, they were excluded from the study. Frequency of admission to hospital
Two hundred seventy-three of the 374 diabetic patients were admitted to Alice Springs Hospital on 694 occasions. The male to female ratio of patients admitted was also 1:1.7. The age and sex distributions, and the proportion they constitute of known diabetic patients, are shown in Fig. 1. Figure 2 shows the mean bed-days per diabetes-year by age group and sex. Of all adult Aboriginal patients admitted to hospital, patients with diabetes accounted for 10.0% and 11.2% of male and female admissions, respectively, and 12.9% and 14.7% of the total bed days. The hospital has 85 beds for adult medical, surgical and gynaecological patients of all races. On
40 r
30I
nales
10 1
Fig. 1. Age distribution
20 1
25-29 IS-19
20-24
of study population
and of patients
0 0 Number of patients
m
35-39 30-34
so-54 45-48 40-44
56-88
60-84
65-89
70-74
75-79
80*
Age Group (years)
admitted
10 3
to hospital
(H).
20 I
J
1
1
30 I
Pecbales
I I
---z
235 Mean bed days/diabetes-year 20 r ~- ~__---
25-34
35-44
45-54
55-64
85-74
‘74
Age group (years) Fig. 2. Mean bed-days per diabetes-year for men (m and women (U), distributed according to age.
any one day, 7 (8.2%) of these beds were occupied by an Aboriginal patient with diabetes. If admissions categorised as ‘other’ are excluded, 5 (5.9%) beds were occupied by Aboriginal patients admitted with conditions related to diabetes. The crude admission rates for men and women per diabetes-year were 0.78 and 0.84, respectively. The number of admissions by age group and sex, the diabetes-years of observation, and relative risks for admission of patients with diabetes are shown in Table 1. The crude relative risks for admission in both sexes did not change after adjusting for age. As there were only 5 admissions in the 15-24-year age group, this group has been excluded from the relative risk analysis. Reason for admission to hospital Table 2 shows the reasons for admission and duration of stay. If inpatient stays for ‘other’ categories (e.g. trauma, 67 admissions; cancer 10 admissions) are excluded, 217 patients (58% of 374) were admitted on 436 occasions (63% of 694) for a condition which could have been precipitated by or associated with diabetes. The crude admission rates of 0.26 and 0.33 per diabetes-year for men and women with ‘other’ conditions are almost identical to the expected rate. Overall, 6.5% of male admissions and 6.9% of Aboriginal Aboriginal female admissions were considered to be related to diabetes. The range, interquartile range and median age
by cause of admission is shown in Fig. 3. Bacterial infection was the most frequent reason for admission (42% and 40% of male and female admissions, respectively). Details on these patients have been published elsewhere [ 121. Of the 24 patients with renal disease (37 admissions), 5 males and 2 females had histologically confirmed diabetic nephropathy. All 7 had proliferative retinopathy as well. In the remaining 17 patients (26 admissions), the contribution of diabetes to renal disease was not known, as renal biopsies had not been performed. Four of the 19 patients admitted with ischaemic heart disease had acute myocardial infarctions, with diagnostic ECG and cardiac enzyme changes. Two of them died within 5 days of admission; neither had any history of angina. There were 7 admissions for acute metabolic complications. Five patients (3 on sulfonlyureas and 2 on insulin) were admitted on 6 occasions for hypoglycaemia. Symptoms included hemiparesis, generalised fitting, and loss of consciousness. All responded immediately to intravenous glucose. A 55-year-old woman with no past history of diabetes was admitted ketoacidosis for precipitated by E. coli septicaemia. Forty-six patients were managed in the intensive care unit for a total of 226 days. Over the 3-year period, 24 patients were transferred by air to Adelaide for more specialised medical care on 32 occasions, a rate of 4 transfers1100 diabetes-years. Of 65 emergency aeromedical evacuations of diabetic patients from rural areas, 42 were for acute infections. Twenty-nine diabetic patients died in hospital during the study period, accounting for 60% of deaths in our cohort. Of these, 13 deaths were due to infection, 5 due to terminal renal failure, and 3 due to strokes. Further details on the case fatality will be presented separately. Underenumeration of diabetes In 1986, 142 patients with diabetes were admitted to hospital according to our data, but only 101 patients had diabetes recorded as a primary or secondary diagnosis in the hospital’s computerised separation data. This yielded an underenumeration of 29%.
240
Total
306.44
25.40 90.75 87.52 42.15 47.13 13.49 0.26
0.24 0.29 0.27 0.26 0.23 0.56
Total
Soft tissue infection Systemic infection Control of glycaemia Renal disease Ischaemic heart disease Cerebrovascular disease Cataracts Other
Cause for admission
34 33 13 9 9 6 2 47 235
53 (22.6) 45 (19.1) 14 (6.0) 13 (5.5) 19 (8.1) 7 (3.0) 3 (1.3) 81 (34.5) 2799
849 636 87 71 148 93 33 882
Mean: 11.9
11.5 11.0 5.5 6.0 6.0 14.0 10.0
44 74 34 15 10 9 3 92
.
533.67
77.0 135.08 152.41 101.10 49.50 18.58
Diabetes years
459
66 (14.4) 117 (25.4) 40 (8.7) 24 (5.2) 17 (3.7) 14 (3.0) 4 (0.9) 177 (38.6)
No. of admissions (%)
n
n
Bed days
Women
Men No. of admissions (%)
449
56 105 109 120 44 15
Median stay (days)
2.92 (2.62-3.26)
2.74 (1.80-4.17) 2.44 (1.97-3.02) 2.61 (2.08-3.28) 3.79 (2.90-4.96) 4.38 (3.31-5.80) 1.20 (0.58-2.48)
Reason for admission to hospital and duration of inpatient stay
TABLE 2
aAdmission rate in adult Aboriginal non-diabetic population
17 64 61 42 47 9
Relative risk (95% CI)
No. of admissions
Expected admission ratea
No. of admissions
Diabetes years
Women
Men
25-34 35-44 45-54 55-64 65-74 >75
Age group (*years)
Age and sex specific diabetes-years of observation and relative risk of admission
TABLE 1
4787
723 1198 406 346 178 526 56 1354
Bed days
0.34
0.44 0.31 0.22 0.18 0.24 0.53
Expected admission ratea
Mean: 10.4
8.0 9.0 7.5 8.5 9.0 7.0 14.5
Median stay (days)
2.46 (2.28-2.66)
1.64 (1.34-2.01) 2.49 (2.1 l-2.94) 3.23 (2.68-3.89) 6.53 (5.42-7.86) 3.64 (2.76-4.80) 1.53 (1.02-2.30)
Relative risk (95% CI)
231
Women
Men
Soft tieeue
t
infection Systemic intection Renal
Control
I.H.D.
C.V.A.
0
IO
20
30
40
60
60
70
60
I
1
I
0
10
20
1
1
1
1
30
40
60
60
’
70
60
Age (years)
Age (years)
Fig. 3. Box plot showing the range, the interquartile range and the median age by cause of admission in men and women.
Outpatient attendances One hundred seventeen men and 215 women attended at least one of the health services as an outpatient in the study period (Table 3). Women TABLE 3 Reason for attendance to outpatient services Reason for attendance
Men n (%)
Women n (%)
Infection Urinary tract infection Respiratory tract infection Soft tissue infection Site uncertain Diabetes follow-up Specialist clinics Medical Eye Renal Other Trauma Hypertension Other
246 (21.8) 9 (0.8) 87 (7.7) 134 (11.9) 16 (1.4) 183 (16.3)
769 (26.3) 236 (8.1) 275 (9.4) 223 (7.6) 35 (1.2) 507 (17.3)
56 (5.0) 30 (2.7) 9 (0.8) 23 (2.0) 108 (9.6) 43 (3.8) 424 (37.8)
226 (7.7) 91 (3.3) 21 (0.7) 89 (3.0) 183 (6.2) 110 (3.7) 926 (31.6)
Total
1122 (100)
2928 (100)
attended health services more frequently than did men. If attendances to specialist referral clinics are excluded, infection accounted for 24.5% and 30.8% of all male and female self-directed presentations to health services (Table 3). Seventeen percent of attendances were for review or treatment of diabetes. Median age of attendance to outpatient services for different causes was similar to that described for hospital admissions, suggesting that the cohorts who were hospitalised did not represent an older subgroup. Over the 3-year period, 769 courses of antibiotics were prescribed to 236 patients, an average of 0.89 courses/diabetes-year.
Discussion
This study differs from many previous studies in that it reports the experience of a cohort of people with diagnosed non-insulin-dependent diabetes, the majority of whom were not treated with insulin. The only report of health service utilisation by
238
Aboriginal patients with diabetes used hospital separation data to compare their admission rates with those of non-Aboriginal patients with diabetes [4]. One drawback of this method is that diabetes frequently is under-recorded as the primary or subsidiary diagnosis at separation. A review at three hospitals in England reported that diabetes was not recorded at separation in 26% of diabetic admissions [ 171; in our study, this occurred in 29% of the admissions. An important limitation of our study is that the results refer only to patients with diagnosed diabetes. As the true prevalence of diabetes in central Australia is at least twice the prevalence of known diabetes [l I], the morbidity from diabetes has probably been exaggerated by our study design. It should also be noted that our study population was identified from health centre data. This is likely to over-represent known diabetic patients with more severe disease, who required regular medical attention. However, our review of all medical records and discussions with urban and rural health staff revealed only 10 patients with diagnosed diabetes who had not attended health services in the study period. Health centres are usually staffed by members of the local community. They have extensive knowledge of their own communities; it is unlikely that a patient with diagnosed diabetes would not have been identified for our study. These results therefore indicate that patients with diagnosed diabetes have severe disease which requires intensive medical care. While the prevalence of known diabetes above 15 years was 3.8% and 6.3% for men and women, respectively [ 111, patients with diabetes accounted for 10.8% of adult Aboriginal admissions to hospital, and 14.0% of hospital bed days. For conditions that are not related to diabetes, the admission rate was similar to that for non-diabetic Aboriginal adults. A less marked, but high admission rate was also reported in New Zealand, where patients with diagnosed diabetes accounted for 1.5% of adults in the community, but 2.2% of all hospital admissions [lo]. The age and sex specific admission rates of patients with diabetes were significantly higher than those for patients who did not have diabetes. The denominators in the latter group were drawn from Australian Bureau of Statistics census data, which
may have underestimated the Aboriginal population by up to 5% [18]. It is possible, therefore, that the relative risk for admission could be even higher than our estimates. Women attended outpatient services more frequently than men, although admission rates were similar. Attendance for routine check-up and education accounted for 17% of attendances. Some of these observations may reflect cultural perceptions of health and health service utilisation, and warrant further study. Bacterial infections were the major reason for admission and accounted for almost one-quarter of outpatient attendances. Few studies have related age distribution to cause of admission, and none have commented on bacterial infection. As expected, slightly older people were admitted with The relatively cardiovascular complications. young age of admission for bacterial infection (median age at admission for soft tissue infection: 45 years for women and 49 years for men) is of concern, and identifies a priority for secondary prevention of complications. The frequent prescription of antibiotics by Aboriginal health workers and nursing staff has generally been encouraged in the rural areas (unpublished observation). Doctors visit at weekly or fortnightly intervals, and specimens for laboratory testing have to be forwarded to Alice Springs, with attendant time delays. Under these circumstances, the generous prescription of antibiotics may have been effective in preventing more severe infections, thus reducing the need for urgent aerial evacuations. The practice reinforces the need to develop standard guidelines for antibiotic use, basing drug selection on common causative organisms and local sensitivity patterns. Ischaemic heart disease and strokes were not major reasons for admission to hospital in our study. The true frequency of these and other atherosclerotic complications requires a more comprehensive assessment. This need is underscored by the high prevalence of the associated risk factors, obesity, hyperinsulinaemia, hypertension and hypertriglyceridaemia in Aboriginal Australians [3]. Studies in the United States have shown that with better care in the community, many diabetic admissions are preventable [19,20]. In New South Wales, Australia, one hospital reduced by two-
239
thirds its hospital bed-occupancy rate for diabetic patients after improving its ambulatory care facilities [21]. A community-based diabetes education and control programme in Victoria reduced diabetes-specific admissions by 82% over 12 months [22]. In central Australia, if admissions for infection alone could be reduced by half, the overall admission of Aboriginal diabetic patients would decrease by 23%, a saving of 568 bed days per year. Our findings stress the need to review current methods of health service delivery to Aboriginal patients with diabetes. Since this study was completed, several community-based diabetes control programs have been established in central Australia. Long-term evaluation of these programs will indicate whether or not they have any effect on the morbidity and health service costs attributable to diabetes.
Acknowledgements
We are grateful to the management and staff of the Alice Springs Central Australian Aboriginal Congress, Hospital and rural health clinics in central Australia. We acknowledge the assistance of Jane O’Sullivan and the Medical Records Departments of Alice Springs Hospital and Royal Darwin Hospital. Dr David Thomas provided valuable suggestions for the manuscript. CBP was supported by a grant from the NH&MRC and by the AMA-AMSA J.G. Hunter Research Fellowship, and worked on the project, in part, towards a Bachelor of Medical Science thesis at the University of Melbourne.
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