PRM217 - Use of Surrogate Outcomes in Health Technology Assessments (HTAs)

Abstract

This study analyzes how frequently surrogate outcomes are used in HTAs and if the validity of these outcomes are discussed and reported within the HTAs. A surrogate outcome is defined by the National Institutes of Health as a biomarker intended to substitute for a clinical endpoint. A surrogate outcome is used when a clinical endpoint of interest is not ideal or does not occur often enough to perform meaningful statistical analysis. It is appropriate to use a surrogate outcome only when there is a strong correlation with the clinical endpoint. Before using surrogate outcomes researchers should confirm that the surrogate outcome is biologically plausible, has a magnitude of association with the clinical endpoint, and reflects changes in the relevant clinical endpoint. Context Matters (CM) analyzed 1,056 HTAs spanning 38 disease conditions. Each HTA had a primary outcome that could be classified as either a surrogate outcome or a clinical endpoint. Data was analyzed for eight HTA agencies: AHRQ, DERP, SMC, HAS, PBAC, NICE, CADTH, and HIS Scotland. For those HTAs using a surrogate outcome as the primary outcome, CM then determined if the HTA agency reported the use of the surrogate and/or discussed the surrogate outcome’s validity. Ninety-one percent of HTAs used a surrogate outcome (966 HTAs), but only 11% (109 HTAs) identified it as a surrogate outcome and/or discussed its validity. The agencies that discussed the use of the surrogate outcome most often were AHRQ, DERP, and HIS Scotland at 48.1%, 28.6%, and 29.0% of the time, respectively. Surrogate endpoints are prevalent in HTAs, but the agencies rarely discuss the validity of these endpoints. All agencies failed to discuss the use of the surrogate endpoint in over 50% of their reviews. HTA agencies are not following best practice use of surrogate outcomes.