Exploration of inequities in prevention and outcomes of cardiovascular disease in Australia

Abstract

The prevention and treatment of cardiovascular disease (CVD), in particular, acute coronary syndrome (ACS), constitute a major economic and social burden globally and nationally. Furthermore, CVD continues to be the leading cause of death and affects patients as well as the healthcare system markedly. Despite the guidelines and policies available to reduce this burden, previous studies suggest that evidence-practice gaps in CVD care and management still exists; therefore, a greater understanding of inequities in healthcare and access to services is needed in order to close these gaps in CVD management. The World Health Organization (WHO) has reported that, across the globe, there are numerous social factors that are associated with health inequities. These inequities reportedly affect outcomes and impose problems for the individuals as well as the healthcare system. In Australia, inequity in the delivery of care has been documented in various chronic disease areas. Populations for whom inequity has been documented include women, those with lower socioeconomic status (SES) and limited English proficiency. Overall, there are a few studies, especially in Australia, describing how these subpopulations are managed in regard to the prevention and the treatment of CVD in primary healthcare, hospital and post-discharge. Therefore, the specific aims of this thesis are to [1] determine the effect of gender on the primary prevention of CVD, the receipt of CVD risk factor assessment and prescription of guideline-recommended medications in Australian primary healthcare; [2] determine the effect of socioeconomic status on ACS patients on the receipt of in-hospital care and clinical outcomes, including major adverse cardiovascular events or death; [3] determine if English proficiency of ACS patients admitted to Australian hospitals has an effect on the receipt of in-hospital care and major adverse cardiovascular events and death in hospital and from admission to follow-up; [4] identify the factors that contribute to household economic hardship following an ACS presentation, on the assumption that this may contribute to the lack of adherence to the appropriate care at post-discharge. For this thesis, two systematic reviews will be performed and the specific aims will be addressed by analysing three Australian datasets. First, the TORPEDO study (N=53,085) which extracted 53,085 patient data at baseline from 40 general practices and 20 Aboriginal community controlled health services. Second, the CONCORDANCE registry which is an ongoing registry which collected over 10,000 patients with suspected or confirmed ACS since 2009 from 42 public hospitals nationwide. Third, the SNAPSHOT ACS which was an observational audit that collected data on 4,387 patients with suspected or confirmed diagnosis of ACS admitted to 286 Australian and NZ hospitals between 14-27 May 2012. For Aim 1, a systematic review was performed to find the pooled effect of gender difference in the assessment of CVD risk factors. Further, TORPEDO data were used to compare the likelihood of primary prevention of CVD by evaluating the risk factor assessment, and further, for those at high-risk of CVD, prescription of medications at primary healthcare services between women and men. For Aim 2, the receipt of individual guideline-recommended medications in patients with ACS compared between the low and the high individual or area-level SES groups was explored through a systematic review. Moreover, CONCORDANCE dataset was used to compare in-hospital care (the receipt of coronary angiogram, revascularisation, a combination of the guideline-recommended medications and referral to cardiac rehabilitation) and clinical outcomes (major adverse cardiovascular event (MACE) and death) between four socioeconomic groups determined by their area of residence. For Aim 3, SNAPSHOT ACS data were used to compare limited English proficient and English proficient patients in regards to their in-hospital care, including the length of stay and the receipt of coronary angiogram, revascularisation, guideline-recommended medications, referral to cardiac rehabilitation smoking cessation advice, dietary advice and physical activity advice, and clinical outcomes, including MACE (myocardial infarction/heart failure/stroke) and death. For Aim 4, SNAPSHOT ACS health economic data were used to examine the factors associated with greater likelihood of experiencing economic hardship following their acute presentation. In terms of results, there was inequitable care for primary prevention of CVD but comparable care and clinical outcomes were observed during the acute presentation to Australian hospitals. For Aim 1, although the pooled international results showed no gender disparity in the assessment of CVD risk, in Australian primary healthcare, women were disadvantaged in receiving weaker primary prevention of CVD than men. In Australia, women had 12% lower odds of being assessed for CVD risk factors (odds ratio (95% confidence interval): 0.88 (0.81, 0.96)). Among patients with CVD or at high CVD risk, women aged 35-54 years were less likely to be prescribed the recommended medications for CVD management (0.63 (0.52, 0.77)), whereas women aged ≥65 years were more likely to be prescribed the medications (1.34 (1.17, 1.54)) compared to their male counterparts. For Aim 2 and Aim 3, the pooled international studies presented the difference in the prescription of guideline-recommended discharge medications, including beta blocker, statin and angiotensin-converting enzyme (ACE), between the lowest and the highest SES groups to patients with ACS in hospital. In Australian hospitals, equitable care was provided to patients with ACS despite their SES or English proficiency during an acute presentation. The likelihood of receiving coronary angiogram, revascularisation, four or more of the five guideline-recommended medication and referral to cardiac rehabilitation were similar across the SES groups. The group with the lowest SES status were found to have higher odds of MACE, driven by the odds of heart failure, however, no significant difference in the odds of short-term and long-term death was found between the groups. Similarly, patients’ proficiency in English did not affect the length of stay, and receipt of coronary angiogram, revascularisation, guideline-recommended medications, referral to cardiac rehabilitation and advice on smoking cessation, diet and physical activity. Further, the likelihood of short-term and long-term MACE and/or death were comparable. For Aim 4, post-discharge, more than 50% of patients who survived ACS reported having experienced economic hardship. Those who were more likely to experience household economic hardship included patients who were younger (18-59 vs ≥80 years: 1.89 (0.77, 4.63)), with no private health insurance (2.04 (1.37, 3.03)), with pensioner concession card (1.80 (1.03, 3.18)) and in low socioeconomic group (lowest vs. highest: 1.77 (0.91, 3.45)). Gender was not associated with experiencing hardship. Overall, this thesis suggests that, in Australia, inequities exist in primary healthcare regarding the prevention and care of CVD between genders, where women are disadvantaged compared to men, but equitable acute care is provided to patients who have presented to a hospital due to ACS, regardless of their SES or English proficiency. Post discharge, patients with low SES are more likely to experience economic hardship which may lead to further inequity in long-term secondary prevention. Although it is an encouraging affirmation that ACS patient care in hospital is not affected by patients’ SES or English proficiency, system-wide solutions are needed to resolve the issue of inequity in primary prevention of CVD and reduce the economic burden of managing ACS to, therefore, reduce the risk of a secondary event.