Is 15 per cent very common? Informing people about the risks of medication side effects

Abstract

Objectives — To assess the general public's interpretation of the verbal descriptors for side effect frequency recommended for use in medicine information leaflets by a European Union (EU) guideline, and to examine the extent to which differences in interpretation affect people's perception of risk and their judgments of intention to comply with the prescribed treatment. Method — Two studies used a controlled empirical methodology in which people were presented with a hypothetical, but realistic, scenario about visiting their general practitioner and being prescribed medication. They were given an explanation that focused on the side effects of the medicine, together with information about the probability of occurrence using either numerical percentages or the corresponding EU verbal descriptors. Interpretation of the descriptors was assessed. In study 2, participants were also required to make various judgments, including risk to health and intention to comply. Key findings — In both studies, use of the EU recommended descriptors led to significant overestimations of the likelihood of particular side effects occurring. Study 2 further showed that the “overestimation” resulted in significantly increased ratings of perceived severity of side effects and risk to health, as well as significantly reduced ratings of intention to comply, compared with those for people who received the probability information in numerical form. Conclusion — While it is recognised that the current findings require replication in a clinical setting, the European and national authorities should suspend the use of the EU recommended terms until further research is available to allow the use of an evidence‐based approach.

A systematic review of quantitative and qualitative research on the role and effectiveness of written information available to patients about individual medicines

“…About 47% of subjects were male, which was reported by all trials except in Berry and colleagues (2004) 109 and in the first trial reported in Berry and colleagues (2002). 105 The ethnic background of participants was not reported in any trials. The participants' education status was reported in all trials except Bergus and colleagues.…”

“…Seven authors (of 10 papers) answered the request for missing data. 34,35,84,87,[103][104][105][109][110][111] Copies of the interventions available (from either the paper or the authors) can be found in Appendix 9.…”

“…35,[105][106][107][108][109][110][111] The remaining trials, which enrolled members of the general public, used information referring to a scenario for a fictitious medicine. [105][106][107][108][109][110] This set of trials is qualitatively distinct from the other trials included in the review because they examined the effect of a single component of the written information, that is, the description of the risk of a side-effect. The majority of these trials were motivated by EU guidance, which defined verbal descriptors for a series of numerical frequency bands of incidence.…”

“…35,[105][106][107][108][109][110][111] Two trials enrolled participants who were currently receiving treatment and provided information about a real medicine. 35,[105][106][107][108][109][110][111] The remaining trials, which enrolled members of the general public, used information referring to a scenario for a fictitious medicine.…”

“…35,[105][106][107][108][109][110][111] Two trials enrolled participants who were currently receiving treatment and provided information about a real medicine. 35,[105][106][107][108][109][110][111] The remaining trials, which enrolled members of the general public, used information referring to a scenario for a fictitious medicine. [105][106][107][108][109][110] This set of trials is qualitatively distinct from the other trials included in the review because they examined the effect of a single component of the written information, that is, the description of the risk of a side-effect.…”