Abstract 19278: The Impact of Chronic Kidney Disease on Clinical Outcomes in Patients Admitted with Acute Myocardial Infraction in an Australian Setting

Abstract

Background: International data suggests the presence of chronic kidney disease (CKD) increases morbidity and mortality following acute myocardial infarction (AMI) and reduces the likelihood of revascularisation. However, the impact of CKD on longer term clinical outcomes and health resource usage remains unclear. Aim: To assess the impact of CKD upon clinical outcomes for patients admitted with AMI.

Methods: New South Wales (NSW) is Australia’s most populous state with an estimated population of 7.2 milllion, representing 32.3% of the total Australian populaton. The NSW admitted patient data collection (NSW APDC) is an administrative coding dataset collecting data on all admissions to NSW hospitals. Coding uses the International Classification of Disease 10 Australian Modification (ICD10 AM). All patients admitted to a NSW hospital with a principle diagnosis of AMI (ICD10 codes: I21.0-I21.3 and I21.4) between 2004 and 2008 were extracted from NSW APDC and linked to the NSW Registry of Births Deaths and Marriages. We analysed outcomes of 30 day, 1 year and medium term (median follow up) all cause mortality, length of stay (LOS) and revascularisation crude rates based on the presence or absence of a diagnostic code of CKD (N18, N19, Z49).

Results: A total of 40,482 patients with AMI were analysed, including 1565 with a CKD code, to a median follow up 3.5 years. Unadjusted analyses of patients coded as having CKD showed higher 30 day mortality (15% versus 7%, p<0.001), 1 year mortality (40% versus 14.5%, p<0.001), 3.5 year mortality (67% versus 25%, p<0.001), LOS (mean 10.4 days versus 7.5 days, p < 0.001) and lower revascularisation rates (14% versus 35%, p< 0.001) compared to those without a CKD code.

Conclusions: Patients admitted to NSW hospitals with an AMI and coding history of CKD have lower rates of intervention, despite significantly higher mortality and length of stay. CKD coding was used infrequently and further research is required to explore the utilisation of CKD diagnostic codes and the poorer outcomes they portend.