Peter Knapp|Peter Gardner|Elizabeth Woolf
Combined verbal and numerical expressions increase perceived risk of medicine side?effects: a randomized controlled trial of EMA recommendations
University of York|University of Leeds|Cancer Research UK Technology
study evaluated european medicines agency ema recommendations communicating frequency information sideeffect riskthe study used 2 2 factorial trial random allocation information 10 sideeffects paclitaxel taxol expressed using one four formats recruitment via cancerhelpuk website information conveyed using numerical frequency bands eg may affect 1 10 people combined verbal terms numerical bands eg common may affect 1 10 people addition risk qualifier verb manipulated risks expressed either affect may affect participants made six sideeffect frequency estimates indicated satisfaction information evaluated sideeffects bad likely risky health influence taking paclitaxelthe sample comprised 339 people 375 cancer combined verbal numerical risk expressions resulted higher estimates sideeffects four reached statistical significance p 005 participants also said sideeffects would likely use may affect affect result differences estimatesthis first evaluation full range combined verbal numerical risk expressions recommended ema guidance demonstrates lead significant risk overestimations compared numerical frequency bands alone ema consider revising guidance government agencies professional bodies cautious recommendations risk communication absence empirical evidence