@article {Fraenkel591, author = {Liana Fraenkel and Dick R Wittink and John Concato and Terri Fried}, title = {Are preferences for cyclooxygenase-2 inhibitors influenced by the certainty effect?}, volume = {31}, number = {3}, pages = {591--593}, year = {2004}, publisher = {The Journal of Rheumatology}, abstract = {OBJECTIVE: To test whether the widespread use of cyclooxygenase-2 (COX-2) inhibitors may be mediated in part by the certainty effect, i.e., by a perception that COX-2 inhibitors eliminate the risk of serious gastrointestinal (GI) events in contrast to merely reduce their risk. METHODS: Patients{\textquoteright} preferences for conventional nonsteroidal antiinflammatory drugs (NSAID) and COX-2 inhibitors for treatment of arthritis were predicted across a range of absolute risks of GI events using an Adaptive Conjoint Analysis survey. RESULTS: Preferences for COX-2 inhibitors were much stronger when the risk of serious GI events was eliminated in contrast to reduced, even though the absolute risk reduction (ARR) was the same. Few patients (22\%) preferred COX-2 inhibitors when the risk associated with NSAID and COX-2 inhibitors was 4\% and 2\%, respectively (ARR = 2\%). In contrast, the majority (90\%) preferred COX-2 inhibitors when the risk associated with NSAID and COX-2 inhibitors was 2\% and 0\%, respectively (ARR = 2\%). We obtained similar findings regardless of the ARR. CONCLUSION: The willingness shown by older adults to pay for COX-2 inhibitors may reflect a misperception of the risk of toxicity associated with these medications.}, issn = {0315-162X}, URL = {https://www.jrheum.org/content/31/3/591}, eprint = {https://www.jrheum.org/content/31/3/591.full.pdf}, journal = {The Journal of Rheumatology} }