Taking a chance on outcome standardisation: A cross-sectional analysis assessing the uptake of the prevention of preterm birth core outcome set in randomised controlled trials

Objective: Analyse uptake of the core outcome set (COS) within preterm birth (PTB) clinical trials. Design: On 26 June 2023, we conducted a systematic search of phase III/IV trial registry entries regarding PTB interventions via ClinicalTrials.gov and the International Clinical Trial Registry Platform. These trials were analysed for the outcomes measured. Setting: N/A. Sample: After searching the two databases, 5257 randomised controlled trials (RCTs) were screened, resulting in 92 RCTs for analysis. Methods: Inclusion criteria were the following: subjects were patients receiving an intervention for PTB, study enrolment began within 5 years prior to publication of PTB COS to 26 June 2023, and evaluated the efficacy of interventions. Authors screened and extracted data in masked, duplicate fashion, then performed an interrupted time series analysis, analysis of variance and correlation analysis. Main outcome measures: We extracted outcomes measured by each clinical trial in our sample. Trials were analysed for the percentage of adopted outcomes from PTB COS. Results: After COS publication, there was no significant change in percentage of COS outcomes measured. The most measured outcome was ‘offspring mortality’ (54.34%, 50/92) and the least measured outcome was ‘late neonatal neurodevelopment morbidity’ (3.26%, 3/92). Additionally, 22.83% (21/92) of trials measured zero outcomes related to the PTB COS. Conclusion: Our results demonstrated no significant change in outcome measurement before or after PTB COS publication. We recommend focusing on both the measurement of outcomes and the assessments that are used.