Surrogate outcomes (DOEs)

A surrogate outcome is a laboratory measurement or a physical sign used as a substitute for a clinically meaningful outcome.

Some examples of surrogate outcomes include:

• Reduction in cholesterol levels with lipid lowering drugs
• Improvement in XRay appearance following knee surgery
• Reduction in anti-depressant use following counseling for depression

The effect of an intervention on a surrogate outcome should predict the effect on the desired clinical outcome. However, the surrogate outcome may be of little interest to the patient. What they want to know is "will I feel better" or "will I live longer"?