Downward trend in the prevalence of hospitalisation for atherothrombotic disease

Complexity in disease management: A linked data analysis of multimorbidity in Aboriginal and non-Aboriginal patients hospitalised with atherothrombotic disease in Western Australia

BACKGROUND

Hospitalisation for atherothrombotic disease (ATD) is expected to rise in coming decades. However, increasingly, associated comorbidities impose challenges in managing patients and deciding appropriate secondary prevention. We investigated the prevalence and pattern of multimorbidity (presence of two or more chronic conditions) in Aboriginal and non-Aboriginal Western Australian residents with ATDs.

METHODS AND FINDINGS

We used population-based de-identified linked administrative health data from 1 January 2000 to 30 June 2014 to identify a cohort of patients aged 25-59 years admitted to Western Australian hospitals with a discharge diagnosis of ATD. The prevalence of common chronic diseases in these patients was estimated and the patterns of comorbidities and multimorbidities empirically explored using two different approaches: identification of the most commonly occurring pairs and triplets of comorbid diseases, and through latent class analysis (LCA). Half of the cohort had multimorbidity, although this was much higher in Aboriginal people (Aboriginal: 79.2% vs. non-Aboriginal: 39.3%). Only a quarter were without any documented comorbidities. Hypertension, diabetes, alcohol abuse disorders and acid peptic diseases were the leading comorbidities in the major comorbid combinations across both Aboriginal and non-Aboriginal cohorts. The LCA identified four and six distinct clinically meaningful classes of multimorbidity for Aboriginal and non-Aboriginal patients, respectively. Out of the six groups in non-Aboriginal patients, four were similar to the groups identified in Aboriginal patients. The largest proportion of patients (33% in Aboriginal and 66% in non-Aboriginal) was assigned to the "minimally diseased" (or relatively healthy) group, with most patients having less than two conditions. Other groups showed variability in degree and pattern of multimorbidity.

CONCLUSION

Multimorbidity is common in ATD patients and the comorbidities tend to interact and cluster together. Physicians need to consider these in their clinical practice. Different treatment and secondary prevention strategies are likely to be useful for management in these cluster groups.

Trends in age- and sex-specific prevalence and incidence of cardiovascular disease in Western Australia

Background Temporal trends in incidence and mortality of cardiovascular disease (CVD) have been well described, with recent data suggesting declining improvements in those aged under 55 years. However, little is known about the combined impact of incidence and mortality trends on disease prevalence, an important indicator of disease burden and cost. We analysed changes in age-specific and age-standardised temporal trends in prevalence and incidence of CVD subtypes. Methods Annual prevalence and incidence rates of coronary heart disease, cerebrovascular disease and peripheral arterial disease for the Western Australian population for 1995-2010 were calculated using data from the Western Australian Data Linkage System. Joinpoint regression analyses were used to identify joinpoints in trends in age-specific and age-standardised annual prevalence and incidence rates for each CVD subtype. Results Between 1995 and 2010, age- and sex-specific incidence and prevalence of the CVD subtypes generally decreased among middle-aged and older adults, but were stable or increased among younger adults. In < 55 year olds, increases in incidence tended to occur from 2003, while increases in prevalence were from 2007/2008. Declines in age-standardised incidence were greater than those in crude incidence, with changes in population structure having a greater impact among men than women. Conclusions The majority of CVDs occurs in older adults. Our findings of generally worsening trends in prevalence in younger adults across most CVD subtypes were in contrast to generally declining trends in older age groups. These data highlight the importance of monitoring prevalence and incidence, particularly in younger adults.

Effectiveness of the cardiac-diabetes transcare program: protocol for a randomised controlled trial

Background

This paper presents a protocol for a randomised controlled trial of the Cardiac-Diabetes Transcare program which is a transitional care, multi-modal self-management program for patients with acute coronary syndrome comorbid with type 2 diabetes. Prior research has indicated people hospitalised with dual cardiac and diabetes diagnoses are at an elevated risk of hospital readmissions, morbidity and mortality. The primary aim of this study is to evaluate the effectiveness (and cost-effectiveness) of a Cardiac-Diabetes Transcare intervention program on 6-month readmission rate in comparison to usual care.

Methods/Design

A two-armed, randomised controlled trial with blinded outcome assessment will be conducted to evaluate the comparative effectiveness of two modes of care, including a Usual Care Group and a Cardiac-Diabetes Transcare Intervention (in addition to usual care) Group. The primary outcome is 6-month readmission rate, although a range of secondary outcomes will be collected (including self-efficacy) at baseline, 1, 3 and 6 month reassessments. The intervention group will receive in-hospital education tailored for people recovering from an acute coronary syndrome-related hospital admission who have comorbid diabetes, and they will also receive home visits and telephone follow-up by a trained Research Nurse to reinforce and facilitate disease-management-related behaviour change. Both groups will receive usual care interventions offered or referred from participating hospital facilities. A sample size of 432 participants from participating hospitals in the Australian states of Queensland and Victoria will be recruited for 90% power based on the most conservative scenarios modelled for sample size estimates.

Discussion

The study outlined in this protocol will provide valuable insight into the effectiveness of a transitional care intervention targeted for people admitted to hospital with cardiac-related presentations commencing in the inpatient hospital setting and transition to the home environment. The purpose of theory-based intervention comprising face-to-face sessions and telephone follow up for patients with acute coronary syndrome and type 2 diabetes is to increase self-efficacy to enhance self-management behaviours and thus improve health outcomes and reduce hospital readmissions.

Trial registration

This study has been registered with the Australian New Zealand Clinical Trials Registry dated 16/12/2014: ACTRN12614001317684.

Temporal trends in initial and recurrent lower extremity amputations in people with and without diabetes in Western Australia from 2000 to 2010

AIMS

To examine temporal trends in lower extremity amputations in people with type 1 diabetes, type 2 diabetes and cardiovascular disease (CVD) without diabetes in Western Australia (WA) from 2000 to 2010.

METHODS

We used linked health data to identify all non-traumatic lower extremity amputations in adults aged ≥20 years with diabetes and/or CVD from 2000 to 2010 in WA. Annual age- and sex-standardised rates of total, initial and recurrent amputations, stratified by major and minor status, were calculated for type 1 and type 2 diabetes, and CVD without diabetes, from the at-risk population for each group. Age- and sex-adjusted trends were estimated from Poisson regression models.

RESULTS

5891 lower extremity amputations were identified. Peripheral vascular disease (71%), hypertension (70%) and chronic kidney disease (60%) were highly prevalent. Average annual rates of total amputations were 724, 564 and 66 per 100,000 person-years in type 1, type 2 diabetes and CVD without diabetes respectively. Rates of initial amputations fell significantly by 2.4%/year (95% CI -3.5, -1.4) in type 2 diabetes, with similar declines for type 1 diabetes and CVD without diabetes (interaction p=0.96), driven by large falls in major amputations. There was limited improvement in recurrence rates overall, with recurrent minor amputations increasing significantly in type 2 diabetes (+3.5%/year, 95% CI +1.3%, +5.7%).

CONCLUSION

Lower extremity amputation rates have declined at a population level in people with diabetes and CVD without diabetes, suggesting improvements in prevention and management for this high-risk patient group, however limited declines in recurrent amputations requires further investigation.

Prevalence of Stroke and Coexistent Conditions: Disparities between Indigenous and Nonindigenous Western Australians

Background

Worldwide, the prevalence of stroke is poorly described in indigenous populations, despite high stroke burden. This paper reports the average point prevalence of hospitalized stroke and coexistent conditions (2007–2011) in indigenous and nonindigenous people in Western Australia, the largest and most sparsely populated Australian jurisdiction.

Methods

Using state-wide linked hospital and mortality data, indigenous and nonindigenous prevalent stroke cases (aged 25–84 years) were identified after reviewing stroke admissions over a fixed 20-year look-back period. Prevalent cases were those alive at midyear of each study year. The 2007–2011 period prevalence was a weighted average of annual prevalence. Histories of 11 comorbidities were identified using the 20-year look-back period.

Results

Indigenous cases comprised 5% of the average 13 591 annual prevalent cases. Indigenous patients were more likely to be younger, female, and have unknown stroke type. Indigenous prevalence was higher at every age. The age-standardized prevalence in indigenous men (33·7 per 1000; 95% confidence interval 31·9–35·4) was 3.7 times greater than in nonindigenous men (9·1 per 1000; 95% confidence interval 9·0–9·2). The corresponding estimates for women were 27·1 per 1000 (25·7–28·4) and 6·1 per 1000 (6·0–6·2) (ratio = 4·4). The percentage with selected comorbid conditions was substantially higher for indigenous patients.

Conclusions

The high stroke prevalence in indigenous Western Australians, coupled with clinical complexity from comorbid conditions, requires access to culturally appropriate medical, rehabilitation, and logistical support. Intensified primary and secondary prevention is needed to reduce the impact of stroke on indigenous people.

Disparities in equity and access for hospitalised atherothrombotic disease

OBJECTIVE

This study of equity and access characterises admissions for coronary, cerebrovascular and peripheral arterial disease by hospital type (rural, tertiary and non-tertiary metropolitan) in a representative Australian population.

METHODS

We conducted a descriptive analysis using data linkage of all residents aged 35-84 years hospitalised in Western Australia with a primary diagnosis for an atherothrombotic event in 2007. We compared sociodemographic and clinical features by atherothrombotic territory and hospital type.

RESULTS

There were 11670 index admissions for atherothrombotic disease in 2007 of which 46% were in tertiary hospitals, 41% were in non-tertiary metropolitan hospitals and 13% were in rural hospitals. Coronary heart disease comprised 72% of admissions, followed by cerebrovascular disease (19%) and peripheral arterial disease (9%). Comparisons of socioeconomic disadvantage reveal that for those admitted to rural hospitals, more than one-third were in the most disadvantaged quintile, compared with one-fifth to any metropolitan hospital.

CONCLUSIONS

Significant differences in demographic characteristics were evident between Western Australian tertiary and non-tertiary hospitals for patients hospitalised for atherothrombotic disease. Notably, the differences among tertiary, non-tertiary metropolitan and rural hospitals were related to socioeconomic disadvantage. This has implications for atherothrombotic healthcare provision and the generalisation of research findings from studies conducted exclusively in the tertiary metropolitan hospitals.