Abstract
Background: Unlike comparable countries, acute coronary syndrome (ACS) mortality is similar between patients who present to rural and urban hospitals in Aotearoa New Zealand (NZ). The aim of this study was to determine whether differences in the occurrence of ischaemic heart disease deaths (IHD) without a preceding hospital admission in rural and urban populations explained this finding.
Methods: In this retrospective observational study, people 20 years and older who died from IHD between July 2011 and December 2018 in NZ were included. The Geographic Classification for Health was used to determine rural-urban status.
The outcome of interest was the lack of a hospital admission preceding IHD death. This was measured at 30-days and 1-year and for all-cause and IHD hospitalisations separately. Analysis was performed in age (<55 years, 55-64 years, 65-74 years and 75+ years) and ethnicity (Māori, non-Māori) strata due to an interaction between these variables.
Results: Of the 37,296 deaths, a similar percentage of rural and urban residents died without an all-cause (rural 63.2%, U2 (large urban areas)-60.8%, U1 (major urban areas)-62.8%) or IHD (rural-70.9%, U2-69.0%, U1-70.1%) admission in the preceding 30 days. Likewise, a similar percentage of deaths occurred without an all-cause (rural-32.8%, U2-35.5%, U1-35.5%) or IHD (rural-52.7%, U2-52.6%, U1-51.9%) admission in the preceding year. Exceptions were deaths that occurred without a prior admission for rural non-Māori aged 55-64 years (higher odds) and 75+ years (lower odds) compared to U1 non-Māori 55-64 years and 75+ years respectively across all four outcome measures. There were few statistically important differences between rural and urban Māori (NZ’s Indigenous population).
Conclusion: This study suggests that the lack of difference in ACS mortality for patients who present to NZ rural and urban hospitals is not explained by IHD death that occurred without a recent preceding hospital admission.
What is known:
• Most deaths from ischaemic heart disease (IHD) occur out of hospital.
• In New Zealand Māori and Pacific peoples are more likely to die out of hospital than non-Māori but unlike similar health systems, a difference between people living in rural and urban areas has not been demonstrated.
• There have been few differences in mortality demonstrated for patients with acute coronary syndrome (ACS) admitted to rural compared with urban hospitals in New Zealand and it has been postulated that this might be due to people dying before being admitted to hospital.
What this study adds:
• Overall, there were few important differences between rural and urban populations that die from IHD without an all-cause or IHD hospital admission in the preceding 30-days or 1-year.
• Rural non-Māori people aged 55-64 years were more likely to die without a hospital admission in the 30 days or 1 year prior to an IHD death compared with non-Māori aged 55-64 years who lived in the most urban (U1) areas.
• Conversely, non-Māori who lived in rural and U2 areas aged 75 years or older were less likely to die without a hospital admission in the previous 30 days or 1 year compared with non-Māori 75 years and older who lived in the most urban (U1) areas.
• There were few differences between rural and urban Māori in IHD deaths that occurred without a hospital admission in the preceding 30 days or 1 year&
• These results are unlikely to account for the lack of difference in mortality between for patients admitted with ACS to rural and urban hospitals.