Assessing the validity of surrogate endpoints in the context of a controversy about the measurement of effectiveness of hepatitis C virus treatment

Surrogate endpoints are often used in clinical trials, as they allow for indirect measures of outcomes (eg, shorter trials with less participants). Improvements in surrogate endpoints (eg, reduction in low density lipoprotein cholesterol, normalisation of glycated haemoglobin) achieved with an intervention are, however, not always associated with improvements in patient-important outcomes. The common tendency in evidence-based medicine is to …