Interim versus final results of the trial—not the flip side of the same coin!

Excerpt

Literature abounds in the interim results of the trial before even its final analysis. Are these interim results reliable and reflective in true sense of the final outcome? The answer is a big “No.” I am reminded of early 2000, when drug eluting stents were introduced, and looking at the interim early results of no restenosis with these stents, Dr.Patrick Serruys from Netherlands famously commented, “If I am in a dream, do not wake me up”. It’s only when the follow-up was allowed to go through its full length, that issues such as the Kounis syndrome, the concertina effect, the late stent thrombosis, mal-apposition, and late aneurysm formation were picked up. The same view is now accorded scientific validity and rigour by a recent publication in JAMA [1]—Among trials that had interim findings published, around 21% drew different conclusions between the interim and final publications. This included one study that found the intervention was harmful in the final publication, whereas the interim report indicated, it was beneficial. Four trials switched from “not different” to “beneficial,” three from “not different” to “harmful/possibly harmful,” six from “beneficial” to “not different,” and one from “Inconclusive” to ‘non inferior,” thus discouraging publications of interim results. …