Sample size calculations in high-profile surgical trials that use patient-reported outcome measures: systematic review

Sample size calculations from high-profile surgical RCTs that used a patient-reported outcome measure as primary outcome were reviewed systematically against Difference ELicitation in TriAls (DELTA2) standards, with a focus on target differences. In this sample of trials, there was frequent use of suboptimal methods to determine the target difference, and sample size calculations were generally not reported to DELTA2 standards. This risks over-recruitment and/or erroneous trial conclusions, which clinicians should be aware of when interpreting published trials.