Drug-induced sudden cardiac death

We have read with great interest the paper which was recently published by Straus et al.1 on the association between the use of non-cardiac QTc-prolonging drugs and the risk of sudden cardiac death (SCD). On the basis of their findings, which were drawn from a large population-based case-control study, the authors concluded that the use of certain non-cardiac drugs that prolong myocardial repolarization is indeed associated with an increased risk of SCD. This study seems to represent an extension of a methodologically almost identical study published in 2004 by the same group.2 This previous study reviewed all cases of death in the Integrated Primary Care Information study between 1 January 1995 and 1 April 2001 (in the recently published paper, the time of observation was extended to 1 September 2003) and concentrated on the association between current use of antipsychotics and SCD. The results of the studies are similar. In the earlier paper, the current use of an antipsychotic drug was associated with a three-fold increase in risk of SCD. In the present article, current use of non-cardiac QTc-prolonging drugs was associated with a similar increase in risk of SCD (adjusted OR: 2.7), although gastrointestinal drugs and antibiotic drugs were included in the analysis. In their final conclusion, the authors extrapolate their results by emphasizing that 320 cases of sudden death per year can be attributed to the use of non-cardiac QTc-prolonging medication in the Netherlands. The authors stress the role of regulatory authorities in the evaluation of the clinical significance of QTc prolongation induced by drugs.