Abstract
Introduction
People living in rural areas of countries similar to Aotearoa New Zealand (NZ) have higher mortality and reduced access to evidence-based interventions and treatments for acute myocardial infarction (AMI) compared to urban areas. Fewer patients with ST-segment elevation myocardial infarction presenting to NZ’s rural hospitals undergo angiography; however, mortality rates were comparable to those presenting to urban hospitals. It is unknown if disparities in care processes and clinical outcomes exist for patients presenting to rural hospitals with non-ST-segment elevation acute coronary syndrome (NSTEACS). Chest pain is a common symptom in people with NSTEACS. The gold standard assessment is an accelerated chest pain pathway that includes a laboratory-based high-sensitivity troponin blood test. However, most NZ rural hospitals rely on point-of-care troponin tests. Chest pain assessment pathways have not been evaluated in rural contexts.
Aim
This thesis aimed to identify differences between the: (1) investigations, treatments, and clinical outcomes for patients with NSTEACS presenting to rural and urban hospitals; (2) rural and urban people who die of ischaemic heart disease (IHD) without a preceding hospital admission; and (3) assess the safety and effectiveness of a Rural Accelerated Chest Pain Pathway (RACPP) using point-of-care troponin. Four related studies were performed. Linked data sets (National Minimum Dataset [NMDS], Mortality collection [MORT], and the All of NZ Acute Coronary Syndrome - Quality Improvement [ANZACS-QI] registry) were used to compare investigations (angiography within 3 days and echocardiogram), treatments (secondary prevention medications), and clinical outcomes (30 day, 1 year and 2 year mortality and hospital readmissions) for patients who presented to rural or urban hospitals with NSTEACS [Studies 1 and 2]. The NMDS and MORT were used to examine rural–urban differences in IHD deaths without a preceding hospital admission [Study 3]. Patients admitted with NSTEACS or those who died from IHD between 2014 and 2019 were included. The RACPP was implemented in 27 rural hospitals, rural general practice and urgent care clinics. The primary outcome was the percentage of 30 day major adverse cardiac events (MACE) [Study 4].
Results
Compared with patients with NSTEACS who presented to urban interventional hospitals, those who presented to rural hospitals had similar odds of dying at 30 days (adjusted odds ratio [OR] 1.02) and 1 year (OR 1.04), but slightly higher odds of dying at 2 years (OR 1.16). A lower percentage of patients who presented to rural compared with urban interventional hospitals underwent angiography within 3 days (63.1% versus 74.3%) or echocardiography (66.3% versus 78.5%). Prescription rates of evidence-based medications were similar for all patients. Comparable percentages of rural and urban residents died without a preceding admission. The RACPP identified 44% of patients as low-risk with no MACE identified.
Conclusion
Patients who presented to rural hospitals had similar mortality rates following NSTEACS to those who presented to urban hospitals. However, patients presenting at rural hospitals were less likely to receive timely investigations. The lack of difference in mortality is unlikely to be explained by patients dying before hospital admission. The RACPP was safe and effective.