Use of a state data bank to measure incidence and prevalence of a chronic disease: end-stage renal failure

Study Protocol:Missing Voices– Communication Difficulties after Stroke and Traumatic Brain Injury in Aboriginal Australians

Background:Aboriginal and Torres Strait Islander Australians experience stroke and traumatic brain injury (TBI) with much greater frequency than non-Aboriginal Australians. Acquired communication disorders (ACD) can result from these conditions and can significantly impact everyday life. Yet few Aboriginal people access rehabilitation services and little is known about Aboriginal peoples’ experiences of ACD. This paper describes the protocol surrounding a study that aims to explore the extent and impact of ACD in Western Australian Aboriginal populations following stroke or TBI and develop a culturally appropriate screening tool for ACD and accessible and culturally appropriate service delivery models.

Method/Design:The 3-year, mixed methods study is being conducted in metropolitan Perth and five regional centres in Western Australia. Situated within an Aboriginal research framework, methods include an analysis of linked routine hospital admission data and retrospective file audits, development of a screening tool for ACD, interviews with people with ACD, their families, and health professionals, and drafting of alternative service delivery models.

Discussion:This study will address the extent of ACD in Aboriginal populations and document challenges for Aboriginal people in accessing speech pathology services. Documenting the burden and impact of ACD within a culturally secure framework is a forerunner to developing better ways to address the problems faced by Aboriginal people with ACD and their families. This will in turn increase the likelihood that Aboriginal people with ACD will be diagnosed and referred to professional support to improve their communication, quality of life and functioning within the family and community context.

The ratchet effect: dramatic and sustained changes in health care utilization following admission to hospital with chronic disease

Supplemental Digital Content is available in the text.

Objective:

To describe the previously unexamined association between admissions to hospital with chronic disease and changes in all-cause health service utilization over time.

Research Design:

A cohort study examining the population of Western Australia with hospitalizations for chronic disease from 2002 to 2010. A “rolling” clearance period is used to define “cardinal events,” that is, a disease-specific diagnosis upon hospital admission, where such an event has not occurred in the previous 2 years. Changes in the rate of cardinal events associated with diagnoses of heart failure, type 2 diabetes, chronic obstructive pulmonary disease, cataract with diabetes, asthma, and dialysis are examined. Health service utilization (defined as inpatient days or emergency department presentations) 6 years preceding and 4 years following such events is presented.

Results:

Cardinal events make up 40%–60% of all chronic disease admissions. A previously undescribed ratchet effect following cardinal events specifically associated with type 2 diabetes, heart failure, and chronic obstructive pulmonary disease is observed. This involves a 2- to 3-fold increase in inpatient days and emergency department presentations that are sustained for at least 4 years.

Conclusions:

Cardinal events represent an important reference point to understand the impact of chronic disease on health service utilization. Events that herald such a marked transition in health service demand have not been previously described.

Assessing the usefulness of health data linkage in obtaining adverse event data in a randomised controlled trial of oral and implant naltrexone in the treatment of heroin dependence

Background

The completeness of self-reported serious adverse events (SAEs) in clinical trials can be reduced by inaccuracies in subject reporting and lost to follow-up.

Purpose

This study assesses the usefulness of a health data linkage system in obtaining SAE data in a randomised controlled study of oral and implant naltrexone.

Methods

SAEs were collected from 68 heroin-dependent subjects during a randomised controlled trial of oral and implant naltrexone with follow-up to 26 weeks. Patient self-report data were cross-matched against hospital and emergency department (ED) attendances for the same period using a health data linkage system.

Results

A total of 29 hospital admissions and 74 ED attendances were identified using health data linkage. Of these, 12 (41.4%) hospital admissions and 50 (67.7%) of ED attendances had not been reported as SAE in the randomised controlled trial. In subjects participating in the trial at the time of the event, there was a 1.25-fold increase in the number of hospital admissions and a 2.25-fold increase in the number of ED attendances recorded using data linkage. Overall (including withdrawn subjects or those lost to follow-up), there was a 1.71-fold increase in hospital admission and a 3.09-fold increase in ED attendance recorded.

Limitations

The use of data linkage should not be used as a replacement for thorough follow-up, as the datasets can take substantial periods to update, making them a poor substitute for real-time follow-up. Additionally, some SAEs such as life-threatening events that do not involve ED or hospital attendance may be overlooked as would SAEs that occurred outside the dataset’s range, for example, interstate or overseas.

Conclusions

Health data linkage can be used to effectively reduce the extent of missing health data in a clinical trial.

Demographic factors as predictors for hospital admission in patients with chronic disease

OBJECTIVE

To identify demographic predictors of hospital admission for chronic disease.

METHODS

Hospital morbidity records were extracted from the WA Data Linkage System for the period 1994-99 for specific chronic diseases based on national priorities. Poisson regression was used to estimate the effects of Aboriginal and Torres Strait Islander (ATSI) descent, co-morbidity, geography, socio-economic status and possession of health insurance on hospital admission rates.

RESULTS

This study has identified some of the main demographic risk factors for hospitalisation in patients with chronic disease as the following: being male, of ATSI descent, living in a relatively disadvantaged Census Collection District and having multiple co-morbidities. Depending on the disease, locational disadvantage and possession of private health insurance were also risk factors.

CONCLUSIONS

The study indicates that a crucial component in keeping patients with chronic disease out of hospital is ensuring quality primary care for all members of the community, equipping patients with the necessary skills to self-manage their chronic condition. Particular attention must be given to developing programs that are accessible to the more disadvantaged members of the community.

IMPLICATIONS

Programs aimed at keeping patients with chronic disease out of hospital must be targeted at the most vulnerable groups of the population if they are to be effective.

Lessons in ethnonephrology

Only recently has the nephrology community moved beyond a fairly singular focus on terminal kidney failure to embrace population-based studies of earlier stages of disease, its markers and risk factors, and of interventions. Observations in developing countries, and in minority, migrant, and disadvantaged groups in westernized countries, have promoted these developments. We are only beginning to interpret renal disease in the context of public health history, social and health transitions, changing population demography, and competing mortality. Its intimate relationships to other health issues are being progressively exposed. Perspectives on the multideterminant etiology of most disease and the pedestrian nature of most risk factors are maturing. We are challenged to reconcile epidemiologic patterns with morphology in diseased renal tissue, and to consider structural markers, such as nephron number and glomerular size, as determinants of disease susceptibility. New work force models are mandated for population-based studies and intervention programs. Intervention programs need to be integrated with other chronic disease initiatives and nested in a matrix of systematic primary care, and although flexible to changing needs, must be sustained over the long term. Cross-disciplinary collaboration is essential in designing those programs, and in promoting them to health-care funders. Substantial expansion and restructuring of the discipline is needed for the nephrology community to participate effectively in those processes.

Antecedents of renal disease in Aborigines

Rates of end-stage renal disease in the Aboriginal community have been increasing over the past two decades, particularly in the northern and more remote areas of Australia, and especially in disadvantaged communities. Proteinuria predicts the rate of loss of renal function and is common in young adults and virtually universal in those over 50 years old. Cumulative independent risk factors include low birthweight, recurrent skin infections, adult obesity, diabetes or its precursors, smoking, excessive alcohol intake and a family history of renal disease. A plausible theory is that intrauterine malnutrition permanently reduces total nephron numbers, which are then overworked in adulthood by the metabolic stresses of obesity (from excess alcohol and poor diet), blood pressure and infections, while starved of blood supply through smoking. Although renal disease is often only detected when already established, there are great rewards for active medical intervention. Control of blood pressure (preferentially using angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II receptor blockers (AIIRB) in combination) can often stop or even reverse kidney damage, despite ongoing poor diabetic control. Adequately funded kidney health programmes with active Aboriginal Health Worker involvement are enormously cost-effective: tight blood pressure control at least halves the rate of disease progression, and every year of dialysis deferred for one patient could fund the appointment of two more health workers. Addressing the underlying social causes for this epidemic is critical.

Deprivation and dialysis: pathways to kidney failure in Australian Aborigines

Rates of end-stage renal disease among Australian Aboriginal people have been increasing over the past 2 decades, particularly in the northern and more remote areas of Australia, and especially in disadvantaged communities. Proteinuria predicts the rate of loss of kidney function; it is common in young adults and virtually universal in those over 50 years of age. Cumulative independent risk factors include low birth weight, recurrent skin infections, adult obesity, diabetes or its precursors, smoking, excessive alcohol intake, and a family history of renal disease. A plausible theory is that intrauterine malnutrition permanently reduces total nephron numbers, which are then overworked in adulthood by the metabolic stresses of obesity (from excess alcohol and poor diet), by higher blood pressures, and by infections, while starved of blood supply because of smoking. Although kidney disease is often only detected when already well established, active medical intervention offers great rewards. Control of blood pressure (preferentially using angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II receptor blockers (AIIRBs) in combination) can often stop or even reverse kidney damage, even if ongoing diabetes control is poor. Adequately funded kidney health programs with active Aboriginal health worker involvement are enormously cost-effective: tight blood pressure control at least halves the rate of disease progression, and every year of dialysis deferred for 1 patient could fund the appointment of 2 health workers. Addressing the underlying social causes for this epidemic is critical.

Improved methods for estimating incidence from linked hospital morbidity data

BACKGROUND

Linked hospital morbidity data can be used to estimate the incidence of serious chronic disease. However, incidence rates calculated from first-time hospital admissions tend to be overestimated as a result of the erroneous inclusion of prevalent cases that have had previous hospital admissions prior to the study observation period. To address this problem, we have developed the backcasting method.

METHOD

A retrograde survival model was implemented to calculate the level of over-ascertainment of incidence according to the number of years of linked data on which the estimates were based and corresponding correction factors were calculated. The method is illustrated using the example of linked hospital morbidity data on diabetes mellitus and then acute myocardial infarction, which was validated against the Perth MONICA database for cardiovascular disease.

RESULTS

Corrected estimates of the incidence of diabetes and acute myocardial infarction were produced. The incidence of diabetes was shown to be lower than in North America in accordance with prevalence estimates, whereas the incidence of acute myocardial infarction was overestimated by approximately 10%.

CONCLUSION

A new method is presented for estimating incidence trends in disease from linked hospital morbidity data. The advantages of this method are its ease of use with routinely collected data and the relatively low cost of applying it in comparison with community surveys or maintaining formal disease registers. The method has other applications using linked data, such as the study of trends in first-time health care procedures and pharmaceutical prescriptions.