Response to Vieweg and Hasnain Letter

Abstract

Back to table of contents Previous article Next article Communications and UpdatesFull AccessResponse to Vieweg and Hasnain LetterBrian L. Strom, M.D., M.P.H.Brian L. StromPhiladelphia, Pa.Search for more papers by this author, M.D., M.P.H.Published Online:1 Jun 2011https://doi.org/10.1176/appi.ajp.2011.11020288rAboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: We appreciate the interest of Drs. Vieweg and Hasnain in our work and the opportunity to be explicit about what the goal of our study was. Drs. Vieweg and Hasnain are concerned that our data may be misconstrued, claiming that we “may have inferred conclusions about ziprasidone and QTc interval prolongation that are not supported by the data.” However, as indicated in our title and throughout the article (1), our goal was to look at comparative rates of nonsuicide mortality. The conclusion of our abstract is explicit: “the study was neither powered nor designed to examine the risk of rare events like torsade de pointes.” The article ends with the following:However, this study was not powered to examine the risk of an extremely rare event like torsade de pointes, which would have required a sample size that was orders of magnitude larger than the 18,154 patients examined in ZODIAC and would have required intensive and prolonged cardiac monitoring, which would have been at odds with the study's goal of adhering to routine clinical care.Thus, we were not studying QTc prolongation and indeed did not even measure it. There has never been any question that ziprasidone prolongs QTc, based on Pfizer's clinical data (2). Our goal was to see whether that led to an increase in nonsuicide mortality.Finally, Drs. Vieweg and Hasnain propose looking at case reports as a way to answer the question they pose, referencing two that they published. While case reports have their place in studying adverse drug reactions (3, 4), they could not have answered the question we were addressing. Furthermore, it is important to keep in mind their substantial limitations. As has often been stated, “The plural of anecdote is not data.”Philadelphia, Pa.The author's disclosures accompany the original article.Accepted for publication in March 2011.