Temporal trends in sudden cardiac death from 1997 to 2010: a data linkage study

Background: Community-wide trends data for sudden cardiac death (SCD) are scarce, unlike widely reported declines in cardiovascular disease (CVD) mortality. Using administrative data, we aimed to examine population-level trends in SCD, stratified by sex, age and prior CVD hospitalisation. Methods: Person-linked mortality and hospital morbidity data were used to identify SCD and determine hospitalisation and comorbidity using a 10-year hospitalisation lookback period. Log-linear Poisson regression was used to calculate annual rate changes and rate ratios. Results: In Western Australia, 7160 SCD cases were identified from 1997 to 2010 with males comprising 69%. Overall age-standardised SCD rates decreased by 17% in men and 31% in women from 1997-2001 to 2007-2010. The annual rate reduction was higher in women than men (-4.0%/year versus -2.3%/year; p=0.0039). Significant reductions were observed for 55-69 year-old and 70-84 year-old men and women but not for the 35-54 year-olds. The overall relative risk comparing men to women increased slightly from 2.4 in 1997 to 3.0 in 2010 (trend p=0.0039) but differed across age groups. The relative risk declined in 35-54 year-olds from 5.1 to 3.2 whereas it increased from 2.9 to 3.9 in 55-69 year-olds and 1.9 to 2.3 in 70-84 year-olds. Declining trends in SCD rates were observed in those with and without prior CVD and were similar to CVD mortality trends (-4.9%/year in men and -5.5%/year in women). Conclusions: Trends in rates of SCD fell in middle to older aged men and women, with and without CVD, and mirrored the fall in fatal CVD. Limited improvement in 35-54 year-olds requires further investigation.