Assessment of patients' preferences for therapeutic outcomes.

We sought to characterize patients' preferences in drug therapy decisions with uncertain outcomes by analyzing their responses to hypothetical therapeutic scenarios. In each scenario, the patient chose between two drugs with equivalent effects, one having two possible outcomes occurring by chance (uncertain outcome) and the other having a single outcome (certain outcome). Most patients chose a certain and intermediate therapeutic effect rather than taking a chance between no effect and a very large favorable effect. When the outcomes were adverse drug effects, there was a strong opposite trend. Rather than preferring a certain and intermediate adverse drug effect, most patients were willing to risk a possible severe drug side effect in order to have a chance of experiencing no adverse reaction. Thus, patients' willingness to accept risks in therapy decisions involving uncertain outcomes may depend on whether the outcomes are favorable or unfavorable.