Determining the outcomes to measure in research into informed consent for therapy
Over the last 25 years, researchers have trialled many different techniques for undertaking the informed consent process for surgery in adults with capacity. Since none of these studies have measured the same outcomes in the same way, we do not know which techniques work best. Furthermore, it appears that the outcomes collected may not be what matters most to patients and doctors. To address these issues, I present the development of a core outcome set for trials of interventions designed to improve consent for surgery. I have developed this core outcome set by: i. investigating which outcomes have been reported in existing research; ii. defining additional outcomes that could be measured through a review of the qualitative literature and a series of semi-structured stakeholder interviews; iii. developing a consent outcomes taxonomy; and iv. determining which outcomes are core through the conduct of an international Delphi survey and a series of consensus webinars. Systematic reviews of existing literature demonstrated that the quality of the informed consent process had largely been evaluated by using recall of consent related information. It was clear from reviewing the protocols of ongoing and planned clinical trials in this field that future research did not plan to evaluate any novel outcomes and again relied on patient recall of information as a marker of quality of the informed consent process. Using the outcomes generated from previous systematic reviews, a qualitative evidence synthesis and the qualitative interviews we asked patient, clinician, consent researcher, bioethicist and lawyer stakeholders to prioritise outcomes for inclusion in a COS. This was conducted over two rounds and included 125 respondents from 8 countries who completed all aspects of both rounds of the survey. Using established consensus building methodology, the survey identified 11 outcomes that met consensus criteria. Many of these had not been reported in existing consent research. These outcomes were taken forward for discussion in a series of online consensus meetings with ‘expert’ stakeholders in order to finalise the COS, with five of the 11 outcomes being judged to be borderline and in need of detailed discussion. The final stage in the development of the COS involved a series of consensus meetings. Two consensus webinars were conducted. Sixteen participants from four countries ratified the inclusion of six outcomes that achieved unanimous ‘consensus in’ criteria during the Delphi survey and voted to include three of the five outcomes that had not achieved unanimous support in the final COS. The final COS consisted of nine outcomes that should be measured in future trials of interventions designed to improve informed consent for invasive procedures. These were: 1. Satisfaction with the quality and amount of information 2. Patient feeling that there was a choice 3. Patient feeling that the decision to consent was their own. 4. Confidence in the decision made 5. Satisfaction with communication 6. Trust in the clinician 7. Patient satisfaction with consent process 8. Patient rated adequacy of time 9. Opportunity to ask questions Having determined “what” to measure in future consent trials, future work should now focus on defining the scope of each outcome, identifying validated tools to measure each outcome or developing and validating novel methods where an appropriate tool does not exist.
Informed Consent, Surgery, Core Outcome Set (COS), Qualitative Evidence Synthesis, Thematic Analysis, Qualitative
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