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A priori consent within pragmatic randomised controlled trials: a web-based survey of statin use in primary care
  1. Alex Semprini1,
  2. Thomas Hills1,
  3. Irene Braithwaite1,
  4. Mark Weatherall2,
  5. Richard Beasley1
  1. 1Medical Research Institute of New Zealand, Wellington, New Zealand
  2. 2University of Otago Wellington, Wellington, New Zealand
  1. Correspondence to Dr Alex Semprini, Medical Research Institute of New Zealand, Private Bag 7902, Wellington 6242, New Zealand; alex.semprini{at}


Background Clinical research methodology is evolving with the advent of pragmatic randomised controlled trials (PRCTs). Novel approaches for informed consent in PRCTs are needed.

Objective To explore public opinion about different ways of giving informed consent for PRCTs.

Design Web-based survey assessing acceptability of three PRCT consent scenarios for statin use.

Setting Community-based study.

Participants 678 (12%) adults responded to an open-access web-based survey.

Measurements Participant-rated acceptability of three different options for giving informed consent for a PRCT testing two commonly prescribed, effective treatments: statins for hyperlipidaemia. Option A was written informed consent given a priori for a specific study, with verbal confirmation of consent at time of randomisation. Option B was written informed, general consent a priori for multiple comparative effectiveness studies, with verbal confirmation for a specific study at time of randomisation. Option C was written informed consent for a specific study at time of randomisation.

Results Acceptability was higher for option A (475/529 (89.9%)) and B (441/487 (90.6%)) compared with C (339/481 (70.5%)). The estimates of differences in paired proportions were A versus C, 19.4% (95% CI 14.4 to 24.5), p<0.001; B versus C, 20.1% (95% CI 15.2 to 25.0), p<0.001.

Limitations The study design may have been subject to cognitive biases such as framing and anchoring effects. The anonymised web-based survey allowed no follow-up or verification for missing data. The sampling frame used an institutional database and social media and selection bias and halo effects may have been present. The 12.3% response rate may represent poor generalisability.

Conclusion The concept of giving a priori consent, with subsequent confirmation at time of randomisation in a PRCT, was more favourable than the traditional model of consent in a general-practice-based study of statin use.

  • consent
  • informed consent
  • ethics
  • pragmatic randomised controlled trial
  • general practice
  • primary care
  • learning health system

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  • Contributors AS, TH, IB and RB designed the study. AS and RB drafted the manuscript and revision. All authors reviewed and edited the manuscript drafts.

  • Funding The Medical Research Institute of New Zealand is supported by the Health Research Council of New Zealand independent research organisation funding. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit the publication.

  • Competing interests None declared.

  • Ethics approval Victoria University of Wellington, New Zealand, Human Ethics Committee; Reference 22859.

  • Provenance and peer review Not commissioned; externally peer reviewed.