Users' guide to the surgical literature: how to assess an article using surrogate end points

Phase 3 randomized controlled trials are the widely accepted gold standard through which treatment decisions are made, as they assess the efficacy of a novel treatment against the control on the relevant patient population. The effectiveness of the novel treatment should be derived by measuring patient-important outcomes; however, to accurately assess these outcomes, clinical trials often require extensive patient follow-up and large sample sizes that can incur substantial expense. For this reason, investigators substitute surrogate end points to reduce the sample size and duration of a trial, ultimately reducing cost. The purpose of this article is to help surgeons appraise the surgical literature that use surrogate end points for patient-important outcomes.