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25-08-2016 | Arrhythmia | News | Article

Sudden cardiac death prediction model developed for general population

medwireNews: Researchers have developed and validated a risk model for predicting sudden cardiac death (SCD) in adults without a history of cardiovascular disease.

Their analysis showed that the model, comprising 12 risk independent risk factors, outperformed the 2013 American College of Cardiology/American Heart Association cardiovascular disease (ACC/AHA CVD) Pooled Cohort risk equation in predicting the 10-year risk of SCD.

“Our findings provide a strong step toward distinguishing SCD risk across the general population and can help target future non-ICD [implantable cardioverter-defibrillator] strategies aimed at SCD prevention for the highest risk subgroups of the general population”, say researcher Rajat Deo (University of Pennsylvania, Philadelphia, USA) and colleagues.

The team evaluated a series of clinical, laboratory, electrocardiographic and echocardiographic measures for 13,677 adults aged 45 years and older without a history of cardiovascular disease participating in the ARIC study.

Over a median follow-up of 13.1 years, there were 171 SCD events. Twelve factors were independently associated with these events. These included increasing age, male gender, African–American ethnicity, being a current smoker, high systolic blood pressure, antihypertensive medication use, diabetes and low high-density lipoprotein levels.

In addition to these variables, which are all present in the 2013 ACC/AHA CVD Pooled Cohort risk equation, increased potassium levels, low albumin concentration, the estimated glomerular filtration rate and an increased corrected QTc interval were selected as risk markers for SCD in the new model.

It is these additional arrhythmia-specific variables that the researchers believe explain the better performance of their SCD risk model compared with the 2013 ACC/AHA CVD Pooled Cohort risk equation, which was developed to provide 10-year risk estimates of SCD but also other cardiovascular events, both fatal and nonfatal.

Including left ventricular ejection fraction in the model did not enhance predictions, the researchers report, noting that the majority of patients had normal values, with values low for just 1.1%.

Over a 10-year follow-up period, the SCD risk model showed good to excellent discrimination for SCD in the ARIC cohort (C statistic=0.820) and this was validated using data for 4207 participants and 174 SCD events from the Cardiovascular Health Study (CHS; C statistic 0.745). These values compared with C statistics for the 2013 ACC/AHA CVD Pooled Cohort risk equation of 0.808 and 0.743 for ARIC and CHS, respectively.

Deo and co-workers also point out in Circulation that the 10-year risk of SCD ranged from less than 1% to 5% among ARIC participants and from 1.5% to 11% among those in CHS, “suggesting that this panel of risk factors can distinguish a large gradient in SCD risk among middle-aged adults.”

They add that as the SCD rates identified in the highest decile of patients were significantly lower than the current clinical thresholds for ICD implantation in the primary prevention of SCD, the model could help target non-ICD strategies for individuals in the general population at highest risk of SCD.

By Lucy Piper

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016

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