Assessing the Uptake of the Core Outcome Set in Randomized Controlled Trial Registrations for the Treatment of Pre-eclampsia Before and After Its Publication

Abstract Objective: To analyze the uptake of the PE COS in randomized controlled trial (RCT) registrations before and after its publication and examined factors associated with its uptake. Methods: PE trials were retrieved from the World Health Organization International Clinical Trials Registry Platform. Two independent reviewers screened for inclusion and extracted data in a masked, duplicate fashion. Trial characteristics and outcomes listed in registry entries were retrieved by reviewing their original registration websites. The COS uptake rate and potential influencing factors in RCT registrations focused on the treatment of PE were assessed, including registration period, prospective registration status, blinding status, sample size, center design, country income level, and intervention type. The consistency of registered outcome definitions with COS recommendations was evaluated. Logistic and negative binomial regression models were used to identify factors independently associated with COS uptake. Results: The post-publication period was independently associated with a higher total number of COS outcomes reported per trial (adjusted risk ratio: 1.53 (1.02–2.29), P = 0.039). Larger sample sizes (≥ 141 participants), multicenter design, interventions involving clinical treatment or delivery mode/timing, and trials conducted in high-income countries were associated with higher COS uptake. Among 279 included RCT registrations, 47.0% ( n = 131) reported at least one specific COS outcome. RCT registrations more commonly adopted maternal COS outcomes ( n = 110, 39.4%) than neonatal outcomes ( n = 60, 21.5%). After adjusting for trial characteristics, the proportion of trial registrations reporting at least one specific COS outcome did not differ significantly between pre- and post-publication periods, either overall (adjusted odds ratio: 1.31 (0.73–2.35), P = 0.361) or within maternal or neonatal outcome domains. Consistency between registered outcome definitions and COS recommendations ranged from 0 to 91.4%, with only two outcomes exceeding 50%. Conclusion: The post-publication period of the PE COS was associated with a higher number of COS outcomes per trial in the overall and maternal outcome domains, but not with a significantly higher likelihood of trial registrations reporting at least one specific COS outcome. However, gaps remained in the neonatal outcome reporting and in the standardization of outcome definitions. Concerted efforts are needed to promote its full uptake and improve reporting quality.