Potential attribute | Potential levels | References |
---|---|---|
Trial characteristics | ||
Involvement of other clinicians | Surgeons only are involved in trial Surgeons and physicians (e.g. neurosurgeon and neurologist) work collaboratively on trial | [45] |
Patient involvement in the trial design | Trial has been designed based on patient perspectives Trial has not had patient input into the design | [45] |
If usual clinician is involved in trial | Usual clinician involved in trial Different clinician involved in trial | [44] |
Study arm allocation | Random allocation to study arm Patient preference for study arm informs allocation | |
Number and type of arms | Two – intervention and placebo Three – intervention and placebo and treatment as usual/non-surgical (e.g. physiotherapy) Three – intervention, placebo one [incision only], and placebo two [more invasive placebo surgery] | [34] |
Randomisation ratio | 1:1 placebo and active intervention 1:2 placebo and active intervention | [37] |
Invasiveness of procedure | Invasive procedure (e.g. joint replacement) Less invasive procedure (e.g. arthroscopy) | [34] |
Invasiveness of placebo arm (including anaesthetic use) | Use of local/regional (with sedation) or general anaesthetic; and size of placebo incision (1-10 cm) | |
Novelty of procedure (including availability outside the trial) | Procedure available outside of the trial Procedure not available outside of the trial (novel) | |
Crossover (availability of procedure if initially assigned to placebo) | Crossover not offered Crossover offered if treatment shown to be effective Crossover offered if desired by patient/ no improvement in symptoms | |
Time to follow up and/or crossover | 3 months 6 months 12 months | |
Financial costs of placebo procedure | Some cost to patient or health system No cost to patient/health system | [37] |
Information and consent procedures | ||
Information about benefits (and likelihood of them) | No benefit to self – benefit to future patients and research/society Possible benefit due to placebo effect – and benefit to future people/research/society Possible benefit to you because of extra care during study visits | |
Patient understanding about procedure and/or study details | Information about the randomisation process, the study arm(s), and their risks will be included in a standard information sheet for patients to read prior to consenting, with patient understanding not checked prior to consent.Information about the randomisation process, the study arm(s), and their risks will be included in an information sheet for patients to read, and then their understanding will be checked to ensure it is sufficient, prior to consenting. | |
Definition/terminology of placebo provided to patient | Use of sham vs placebo Standard definition of placebo provided to patient Placebo defined in patient-centred terms, with opportunity for questions | [36] |
Comprehensive provision of information about all possible outcomes (including risks) | Patients are informed of possible outcomes and risks through standard discussion with surgeon prior to surgery Patients are informed of possible outcomes and risks through a discussion with a research coordinator in addition to the standard discussion with surgeon prior to surgery | |
Patient involvement in the consent process (e.g. writing consent in own hand, pre-agreed discussions, formal decision aids) | Standard information and consent form only Information and consent forms accompanied by patient-centred discussion & formal decision aids | [36] |
Surgeon involvement in the consent process (and format) | Surgeon involved in consent procedure Surgeon not involved in consent procedure | [40] |