Does delay in planned diabetes care influence outcomes for aboriginal Australians? A study of quality in health care

BACKGROUND

To examine the association between delay in planned diabetes care and quality of outcomes.

METHODS

A retrospective analysis of primary care and inpatient records for 2567 Aboriginal patients, with diabetes, living in 49 remote communities in the Northern Territory of Australia. Poisson regression was used to estimate the association between delay from diagnosis to documented diabetes care plan and three outcome measures: mean HbA1c level, most recent blood pressure and number of diabetes-related hospital admissions.

RESULTS

Compared with no delay (< 60 days), patients with delay had increased risk of elevated mean HbA1c: 60 days to < 2 years, incidence rate ratio (IRR), 1.2 (95% CI:1.07-1.39); 2 years to < 4 years, incidence rate ratio (IRR), 1.2 (95% CI:1.04-1.45); 4 years and over, incidence rate ratio (IRR), 1.3 (95% CI:1.12-1.52). There was no evidence of association between delay and optimal blood pressure control. Risk of diabetes-related admission increased with increased delay. Compared with no delay the IRRs for delay were: 60 days to < 2 years, 1.2 (95% CI:1.07-1.42); 2 to < 4 years, 1.3 (95% CI: 1.15-1.58): and 4 years and over, 2.6 (95% CI,2.28-3.08).

CONCLUSION

The study found that a timely diabetes care plan was associated with better short-term blood glucose control and fewer diabetes-related admissions but not with improved blood pressure control. Delays may be a result of both patient and service-related factors.

Effect of ambient temperature on Australian northern territory public hospital admissions for cardiovascular disease among indigenous and non-indigenous populations

Hospitalisations are associated with ambient temperature, but little is known about responses in population sub-groups. In this study, heat responses for Indigenous and non-Indigenous people in two age groups were examined for two categories of cardiac diseases using daily hospital admissions from five Northern Territory hospitals (1992-2011). Admission rates during the hottest five per cent of days and the coolest five per cent of days were compared with rates at other times. Among 25-64 year olds, the Indigenous female population was more adversely affected by very hot days than the non-Indigenous female population, with admission rates for ischaemic heart disease (IHD) increasing by 32%. People older than 65 were more sensitive to cold, with non-Indigenous male admissions for heart failure increasing by 64%, and for IHD by 29%. For older Indigenous males, IHD admissions increased by 52% during cold conditions. For older non-Indigenous females, increases in admissions for heart failure were around 50% on these cold days, and 64% for older Indigenous females. We conclude that under projected climate change conditions, admissions for IHD amongst younger Indigenous people would increase in hot conditions, while admissions among elderly people during cold weather may be reduced. The responses to temperature, while showing significant relationships across the Northern Territory, may vary by region. These variations were not explored in this assessment.

Clustering in Northern Territory perinatal data for 2003-2005: implications for analysis and interpretation

Clustering in perinatal data can violate assumptions of independence, an important consideration for data analysis. Few published studies report on the extent of repeat births in routinely collected Australian perinatal data and the implications thereof for analysis and interpretation. This paper reports on a case study that examined the extent and implications of clustering in the Northern Territory Midwives Collection (NTMC) for the period 2003-2005. Data were obtained on 7,741 individual mothers giving birth to 8,707 babies in public hospitals during 2003-2005. Clusters of multiple pregnancies and repeat births were identified and the design effects for birth weight of Aboriginal and non-Aboriginal newborns were calculated. Of the mothers, 46.1% were Aboriginal. Of these, 13.2% had repeat singleton births; 0.4% had multiple pregnancies, and 0.3% had both. Of non-Aboriginal mothers, 8.7% had repeat singleton births; 1.2% had multiple pregnancies; and 0.3% had both. The design effect was 1.07 for Aboriginal newborns and 1.04 for non-Aboriginal newborns. The design effects indicate that the correct variance accounting for clustering is 4-7% larger than the incorrect variance ignoring clustering when three consecutive years of NT data are considered and an intracluster correlation coefficient of 0.48 is assumed for birth weight between twin and non-twin siblings. Depending on the outcome of interest, the impact of clustering should be considered in multivariate analysis of perinatal data, especially when such analyses involve more than one year’s data, include large proportions of Aboriginal mothers and newborns, and groups with different rates of repeat births.

Validation and enhancement of Australian Aboriginal and Torres Strait Islander psychiatric hospitalisation statistics through an Indigenous Mental Health Worker Register

INTRODUCTION

Inaccuracy in identification of Indigenous status on health records hampers collection of the good quality data required to guide policies, programs and services. This study examined the use of an Indigenous Mental Health Worker Register to assess the level of correct identification of Indigenous status and sources of error among psychiatric admissions within a regional public hospital information system.

METHOD

The study was conducted in 2004/2005 and 2005/2006 at the Cairns Base Hospital Mental Health Unit, Queensland, Australia, serving a population of 230,000 of which 13.2% identify as Aboriginal and/or Torres Strait Islander. Psychiatric admissions data, including Indigenous status, accessed from the hospital-based corporate information system (HBCIS) were compared with data collected through an Indigenous Mental Health Worker Register that is maintained through extensive networking. Investigation of mismatches enabled estimation of the frequency and sources of incorrect identification of Indigenous status and the impact of this on hospital statistics.

RESULTS

Cross-validation of HBCIS data with the Indigenous Register over 2 years revealed 355 Indigenous admissions. Of the total 355 admissions, 301 (84.8%) were correctly identified and included in the hospital system, while 22 (6.2%) were designated non-Indigenous, 13 (3.7%) were 'unspecified' and 19 (5.4%) were missed through incorrect residence or admission designation. Among 1293 non-Indigenous admissions, 1.1% were incorrectly identified as Indigenous, while 25.5% of the 51 with unspecified status were found to be Indigenous. Furthermore, 45 Indigenous separations that had been missed over the previous 5 year period (1999/2000 to 2003/2004) were identified through careful examination of all those with unspecified status (n=174) and those with multiple separations of mixed designation of Indigenous status (n=15); all of the latter 15 were confirmed Indigenous by other mental health database and/or the Indigenous Mental Health Worker. Thus overall this study revealed a total of 89 Indigenous separations and 1261 occupied bed days in the 7 year period that had not be identified in the hospital information system.

CONCLUSION

A novel method was used to ascertain the reliability of Indigenous status identification among mental health admissions within a hospital information system in a region with relatively high Indigenous population representation. This revealed that 85% of admissions were correctly identified over two consecutive years. Perhaps more importantly, the study confirmed a low frequency of false identification of non-Indigenous people as Aboriginal and/or Torres Strait Islander. The work has also demonstrated the value of involving Indigenous Mental Health Workers in routine processes to enhance, validate and improve Indigenous statistics and increase access to culturally informed care.

Central corneal thickness of indigenous Australians within Central Australia

PURPOSE

To document the central corneal thickness (CCT) among a group of Indigenous Australians compared with a group of Australian Caucasian individuals.

DESIGN

Clinic-based case-control study.

METHODS

A total of 91 Indigenous Australians from remote clinics in Central Australia and 84 Caucasian subjects from a teaching hospital in South Australia were recruited. Each subject underwent ultrasound pachymetry, and results were compared between groups.

RESULTS

Mean +/- SD CCT for Indigenous Australians for right and left eyes, respectively, was 511 +/- 34 microm and 513 +/- 35 microm; and 541 +/- 31 microm and 543 +/- 33 microm in Caucasian subjects (t = 6.96; P < .0001 for right eyes and t = 6.56; P < .0001 for left eyes).

CONCLUSIONS

Indigenous Australians exhibit CCT that is significantly lower than that of Caucasian subjects. Given that Indigenous Australians are considered to be at very low risk of developing glaucoma, low CCT values alone may not be sufficient to increase the risk of developing glaucoma in a particular race.

Cancer diagnosis and treatment in the Northern Territory: assessing health service performance for indigenous Australians

Indigenous Australians with cancer are diagnosed with more advanced disease and have lower survival than other Australians. To investigate reasons for these differences. Retrospective cohort study of 1197 indigenous and nonindigenous people in the Northern Territory diagnosed with cancers of the colon and rectum, lung, breast, cervix and non-Hodgkin lymphoma between 1991 and 2000. Outcome measures were stage at diagnosis and relative risk of cancer death. Indigenous people compared with nonindigenous people had higher relative odds of advanced stage of cancer at diagnosis (relative odds 1.9, 95% CI 1.3-2.7) for four cancers but lower relative odds for lung cancer (relative odds 0.3, 95% CI 0.2-0.5). None of the potentially contributing factors examined could explain this difference. Risk of cancer death (adjusted for cancer type and age and stage at diagnosis) was higher in indigenous than in nonindigenous people (relative risk 1.7, 95% CI 1.4-2.1). This difference, however, was confined to indigenous people with an indigenous first language (relative risk 2.9, 95% CI 2.2-3.8). Adjustment for cancer treatment variables further reduced but did not eliminate this higher risk of death. Although more advanced stage at diagnosis appeared to be a sufficient explanation for poorer cancer outcome in indigenous people whose first language was English, poorer treatment also contributed to, but was still not sufficient to explain, poorer outcome in those who had an indigenous first language. Other factors, possibly including communication difficulties, knowledge of and attitudes to cancer symptoms and treatment and social and cultural 'distance' from mainstream health services, may also be involved.

Prevalence of cicatricial trachoma in an indigenous population of Central Australia: the Central Australian Trachomatous Trichiasis Study (CATTS)

BACKGROUND

Trachoma is one of the leading causes of blindness worldwide, resulting from conjunctival scarring, upper lid entropion and trichiasis, leading to corneal scarring and opacification. This study was designed to investigate the current prevalence of cicatricial trachoma in an indigenous population within Central Australia and help determine whether trachoma remains a public health issue.

METHODS

Participants aged 40 and over were recruited from patients attending one of 16 remote ophthalmology clinics held at indigenous communities in Central Australia within the Northern Territory. Once informed consent had been obtained, each patient underwent examination for evidence of trachomatous scarring, trachomatous trichiasis and corneal opacities. Results were collated and compared with previous prevalence surveys.

RESULTS

Among the sample (n = 181), there were 97 patients (54%; 95% CI 46.7-61.3) with trachomatous scarring, 15 patients (8%; 95% CI 2.8-13.2) with trichiasis and 5 patients (3%; 95% CI 0.5-5.5) with corneal opacities.

CONCLUSION

This study suggests that, although the prevalence of the cicatricial and blinding consequences of trachoma may be decreasing in patients aged 40 years or greater, when compared with the current prevalence in other areas of Australia, trachoma still remains a public health issue in Central Australia.

Modelling of endemic carriage of Haemophilus influenzae in Aboriginal infants in Northern Australia

Aboriginal infants and children in rural communities in Northern Australia have high rates of nasopharyngeal carriage of nonencapsulated Haemophilus influenzae (NCHi), with positive swab rates of 76%. In this population, the acquisition of NCHi from soon after birth is associated with the onset of otitis media and with muco-purulent nasal discharge, while the long-term persistence of NCHi carriage is associated with the acquisition and turnover of large numbers of antigenically diverse strains. Mathematical models have been fitted to data on the acquisition and loss of encapsulated strains of H. influenzae and 43 different strains of NCHi in 10 children followed from early infancy for up to 2 years. Subject to plausible assumptions, the preferred model estimated the mean time to acquisition of a H. influenzae strain to be 7 days after first becoming exposed after birth. For an infant already carrying H. influenzae, each additional strain was acquired after a mean waiting period of 45 days. On average, 1.50 different strains of H. influenzae were detected in four colonies routinely typed from each positive swab, but it was estimated that another 2.55 strains were 'hidden' behind these more frequent strains. With an average of 4.05 strains per carrier, it was estimated that each strain was carried for an average of 137 days, although detected on only 37% of occasions. Thus we have developed mathematical models that provide estimates for duration of colonisation, time to colonisation, and number of colonising strains in a population in which H. influenzae is highly endemic, characterised by sequential and concurrent carriage of multiple strains in each infant.

Intestinal permeability and diarrhoeal disease in Aboriginal Australians

BACKGROUND

Northern Territory Aboriginal children hospitalised with acute gastroenteritis have high rates of acidosis, hypokalaemia, and dehydration.

AIMS

To determine whether Aboriginal children with and without diarrhoea have greater impairment in intestinal function than non-Aboriginal children, as assessed by increased permeability ratios.

METHODS

A descriptive study of 124 children (96 Aboriginal and 28 non-Aboriginal) hospitalised with and without diarrhoea. Intestinal permeability was assessed by the lactulose to rhamnose (L-R) ratio from a five hour urine collection.

RESULTS

In Aboriginal children, mean L-R ratios (95% confidence intervals) were 18.3 (17.1 to 19.6) with diarrhoea and 9.0 (7.3 to 11.0) without diarrhoea, and in non-Aboriginal children they were 5.9 (2.8 to 12. 3) and 4.2 (3.3 to 5.2), respectively. In patients with diarrhoea, L-R ratios were significantly raised when accompanied by acidosis (mean, 22.8; 95% CI, 17.0 to 30.5), hypokalaemia (mean, 20.7; 95% CI, 15.4 to 27.9), and >/= 5% dehydration (mean, 24.3; 95% CI, 19.0 to 29.6) compared with none of these complications (mean, 7.0; 95% CI, 3.5 to 13.8).

CONCLUSION

The high incidence of acidosis, hypokalaemia, and dehydration in Aboriginal children admitted with diarrhoeal disease is related to underlying small intestinal mucosal damage.

Carriage of multiple ribotypes of non-encapsulated Haemophilus influenzae in aboriginal infants with otitis media

Ribotyping with the restriction enzyme XbaI was used to study the dynamics of Carriage of non-encapsulated Haemophilus influenzae (NCHi) in Aboriginal infants at risk of otitis media. Carriage rates of NCHi in the infants in the community were very high; the median age for detection was 50 days and colonization was virtually 100% by 120 days of age and persisted at a high level throughout the first year of life [1]. Eighteen different ribotypes of NCHi were identified from 34 positive swabs taken from 3 infants over a period of 9 months. The same ribotypes were recovered for up to 3 months from consecutive swabs of individual infants, and 12 of 27 swabs (44.4%) yielded two ribotypes from four colonies typed. Statistical analysis suggested that most swabs would have been positive for two ribotypes if enough colonies had been typed although the second most frequent ribotype was detected on average in only 13% of strains. Early colonization and carriage of multiple ribotypes of NCHi may help to explain the chronicity of carriage and thus the persistence of otitis media in Aboriginal infants.

Cardiac pathology and adult aboriginal mortality: a coronial study of sudden and external cause deaths in the top end of the Northern Territory in 1990

A retrospective review of coronial records was performed for 179 adult decedents who came to coronial autopsy in 1990 and who had been living in the Top End of the Northern Territory at the time of death. The directly standardized rate of autopsy-examined sudden death was 7.4 times higher for Aboriginal people than for non-Aboriginal people. Coronary atherosclerosis was the cause of 37% (14/38) of the Aboriginal sudden deaths and 52% (16/31) of the non-Aboriginal sudden deaths. Evidence of coronary atherosclerosis rose with age and was seen more frequently in those dying suddenly compared to those dying of external causes. When directly standardized, the rate of autopsy-examined sudden death attributable to ischemic heart disease was 5.5 times higher for Aboriginal people than for non-Aboriginal people. Contrary to a previously published statement, there is considerable overlap between Aboriginal and non-Aboriginal heart weights, with 75% (55/73) of Aboriginal decedents and 84% (89/106) of non-Aboriginal decedents having heart weights between 250 and 500 g. We concluded that the rate of autopsy-examined sudden death from all causes, and specifically from ischemic heart disease, was much higher in Aboriginal people. However in a case of sudden death a presumptive clinical diagnosis of ischemic heart disease prior to autopsy is not justified in either Aboriginal or non-Aboriginal people, due to the high prevalence of other fatal conditions. The diagnosis of pathologically increased heart weight, which is critical in the assessment of sudden death, should be made on the same basis in both Aboriginal and non-Aboriginal people.

Hepatitis B virus markers in children and staff in Northern Territory schools

OBJECTIVE

To measure the prevalence of hepatitis B virus (HBV) infection in children and staff at Northern Territory schools.

DESIGN

Children in Years 5-7 in 24 selected primary schools were invited, with parental consent, to provide demographic and ethnic details, and a capillary blood sample for tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBs). School staff participated on a similar basis.

PARTICIPANTS

1104 children, comprising 556 from ethnic groups (originating from the United Kingdom, Ireland and northern Europe) previously reported as "low HBV prevalence", 439 Aboriginal Australians, and 109 from "other" ethnic groups (originating from Asia, the Pacific, the Middle East and southern Europe); and 209 school staff, comprising 180 from "low HBV prevalence" ethnic groups, and 29 from Aboriginal and other ethnic groups.

RESULTS

Prior HBV infection (i.e. serum positive for HBsAg or anti-HBs) was detected in 28.7% of children (46.9% of 439 Aborigines; 13.7% of the 556 children from the "low prevalence" groups and 32.1% of the 109 from the "other" groups). HBsAg was detected in 8.2% of Aboriginal children, in 0.36% of those from "low prevalence" groups, and in 1.8% of those from the "other" groups. Aboriginal children in rural schools had the highest prevalence of HBV: 5.4% were positive for both HBsAg and anti-HBs, and an additional 9.8% were positive for HBsAg alone. In urban schools, the prevalence was highest in the "other" ethnic groups. For school staff, the prevalence of HBV infection was 12.8% for those from "low prevalence" ethnic groups, and 37.9% for those from all remaining groups (including Aborigines).

CONCLUSION

In the Northern Territory the prevalence of past HBV infection is high in children and school staff from ethnic groups previously known to be at higher risk of HBV infection. For students and staff from ethnic backgrounds expected to be at low risk, HBV prevalence is greater than in individuals from similar backgrounds in other parts of Australia. HBV vaccination is now offered to all infants in the Northern Territory. These results also provide a rationale for the more widespread use of HBV vaccine in other situations where significant HBV transmission might occur.

The epidemiology of invasive Haemophilus influenzae infections in children under five years of age in the Northern Territory: a three-year study

A survey of all episodes of invasive Haemophilus influenzae infections that were diagnosed over a three-year period in children seen at the regional hospitals of the Northern Territory has found a significantly (P less than 0.001) higher incidence in children in Central Australia (the Alice Springs and Barkly regions, and the Anangu Pitjantjatjara Lands) than in the Top End (the Darwin, East Arnhem and Katherine regions), and a greater incidence in Aboriginal than in non-Aboriginal children. Identified risk factors for Aboriginal children were infancy (more than 70% of cases occurred before 12 months of age), sex (with a predominance in girls) and residence in Central Australia; the estimated annual incidence for Central Australian Aboriginal children was 991 cases per 100,000 children. There was a significant correlation (r = 0.62) between the total number of cases diagnosed each month in Central Australia and the mean monthly temperatures recorded in Alice Springs. Whereas virtually all cases of invasive H. influenzae infection in non-Aboriginal children were caused by type b strains, strains other than type b caused 15% of the cases in Aboriginal children. The possibilities for prevention by immunization are discussed.