The core 14 trials in the CTT papers – Diet and Health Today

Introduction

We’re in the middle of three notes looking at the seminal statin trials and the six papers published by the Cholesterol Treatment Trialist (CTT) group, which pooled these trials together. Last week we summarised the six key papers, what the primary objective was for each paper and which trials were included in each paper. The intervention for each trial (statin vs placebo or higher vs lower dose statin) and the scale of industry involvement were also summarised.

With that as background, this note looks in more detail at 14 trials. This is because 14 trials were included in all 6 meta-analyses. Only 3 of these 14 trials claimed a benefit for mortality (as we saw with the de Lorgeril analysis from the 4S Monday note) (Ref 1). These three determined the result for mortality overall. Once it is known that 14 trials elicit a result, more trials can be added to these 14 with the confidence that a result will continue to be found. The first CTT meta-analysis (2005) involved 14 trials. The last CTT meta-analysis (2019) involved 28 trials. Provided that trials 15-28 don’t have striking results against statins, adding more trials won’t change and might strengthen the original findings.