Sudden cardiac death rates in an Australian population: a data linkage study

Abstract

Objective The aim of the present study was to develop criteria to identify sudden cardiac death (SCD) and estimate population rates of SCD using administrative mortality and hospital morbidity records in Western Australia. Methods Four criteria were developed using place, death within 24 h, principal and secondary diagnoses, underlying and associated cause of death, and/or occurrence of a post mortem to identify SCD. Average crude, age-standardised and age-specific rates of SCD were estimated using population person-linked administrative data. Results In all, 9567 probable SCDs were identified between 1997 and 2010, with one-third aged ≥35 years having no prior admission for cardiovascular disease. SCD was more frequent in men (62.1%). The estimated average annual crude SCD rate for the period was 34.6 per 100 000 person-years with an average annual age-standardised rate of 37.8 per 100 000 person-years. Age-specific standardised rates were 1.1 per 100 000 person-years and 70.7 per 100 000 person-years in people aged 1–34 and ≥35 years, respectively. Ischaemic heart disease (IHD) was recorded as the underlying cause of death in approximately 80% of patients aged ≥35 years, followed by valvular heart disease and heart failure. IHD was the most common cause of death in those aged 1–34 years, followed by unspecified cardiomyopathy and dysrhythmias. Conclusions Administrative morbidity and mortality data can be used to estimate rates of SCD and therefore provide a suitable methodology for monitoring SCD over time. The findings highlight the magnitude of SCD and its potential for public health prevention. What is known about the topic? There is considerable variability in rates of SCD worldwide. Different data sources and varied methods of case ascertainment likely contribute to this variation. What does this paper add? The rate of SCD in Australia is low compared with international estimates from USA, Ireland, Netherlands and China. Two in every three cases of SCD aged ≥35 years had a hospitalisation history of cardiovascular disease, highlighting the opportunity for prevention. What are the implications for practitioners? High-quality person-linked administrative hospital morbidity and registered mortality data can be used to estimate rates of SCD in the population. Understanding the magnitude and distribution of SCD is imperative for developing effective public health policy and prevention measures.