Journal Club Summary

Methodology Score: 3.5/5              
Usefulness Score: 3.5/5
Jones AE, Shapiro NI, Trzeciak S, Arnold RC, Claremont HA, Kline JA; Emergency Medicine Shock Research Network (EMShockNet) Investigators.
JAMA. 2010 Feb 24;303(8):739-46.
This multi-centre, randomized, non-inferiority trial looked at using lactate clearance of 10% instead of ScvO2 as the tissue oxygen delivery target in early goal directed therapy for severe sepsis and showed a mortality difference of -6% (95% CI -3% to 15%; non-inferiority D -10%). Despite some limitations in the study, JC attendees were encouraged by the findings to support the use of lactate clearance in the ED instead of ScvO2 measurements for EGDT in severe sepsis and septic shock. 
By: Dr: Andy Pan
(Presented June 2013)

Epi Lesson: Equivalence or Non-Inferiority Trials     

Most RCTs aim to determine whether one intervention is superior to another (superiority trials). Often a non-significant test of superiority is wrongly interpreted as proof of no difference between the two treatments. By contrast, equivalence trials aim to determine whether one (typically new) intervention is therapeutically similar to another (usually existing) treatment. A non-inferiority trial seeks to determine whether a new treatment is no worse than a reference treatment. Because proof of exact equality is impossible, a pre-stated margin of non-inferiority (delta) for the treatment effect in a primary patient outcome must be defined a priori. Equivalence trials are very similar, except that equivalence is defined as being within pre-stated a two-sided treatment effect. True (2-sided) equivalence therapeutic trials are rare.  
By Dr. Ian Stiell