In ICER analysis, what characterizes extended dominance?

• A. Extended dominance occurs when a combination yields a better ICER than an alternative.
• B. Extended dominance means the cheapest option is always chosen.
• C. Extended dominance means the most effective option always has the lowest ICER.
• D. Extended dominance is unrelated to ICER.

Answer: (A)

In cost-effectiveness analysis, extended dominance means an option is less efficient than a combination of two other options. After ordering interventions by increasing effectiveness and calculating the incremental ICERs between adjacent options, if an option’s ICER is higher than the ICER of a more effective option, that option is extendedly dominated and can be dropped from consideration. This reflects the idea that a blend of two other choices would achieve the same or better improvement in effect at a better cost per unit of effect.

So the statement that extended dominance occurs when a combination yields a better ICER than an alternative captures this concept: a single option is not the most efficient use of resources because a mix of other options provides a more favorable ICER. The other choices don’t fit: simply choosing the cheapest option isn’t how ICER decisions work; the most effective option doesn’t always have the lowest ICER; and extended dominance is specifically tied to ICER comparisons, not unrelated.