Enhancing reporting and interpretation of surrogate endpoints in rehabilitation randomized controlled trials: a scoping review.

Abstract

This study aimed to identify and audit rehabilitation randomized controlled trials (RCTs) that used surrogate endpoints, evaluating the completeness and transparency of reporting based on the recently developed SPIRIT- (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT- (Consolidated Standards of Reporting Trials) surrogate extension checklists. A scoping review was performed, analyzing RCTs from the MEDLINE, PEDro, CINAHL, EMBASE, and SCOPUS databases up to April 29^th, 2025. Included studies involved live human participants and investigated non-pharmacological interventions affecting health outcomes, with surrogate endpoints linked to target outcomes. Both qualitative and quantitative analyses were conducted using the SPIRIT and CONSORT-surrogate checklists for reporting compliance. Out of 3,316 records, 20 RCTs were included. Most studies were published between 2004 and 2024, primarily post-2011 and from high-income countries. All three protocol registries found scored zero on the SPIRIT-surrogate checklist. Multiple surrogate endpoints were identified, chiefly as biomarkers. Only 30% (<i>n</i> = 6 RCTs) met at least 50% of the CONSORT-surrogate checklist items in their final reports. Surrogate endpoints are infrequently utilized or reported inconsistently as primary outcomes in rehabilitation RCTs. There's a need for improved reporting quality in rehabilitation RCTs using surrogate endpoints in line with SPIRIT and CONSORT-surrogate checklists. Implications for rehabilitationRandomized controlled trials are key contributors to evidence-based care in the rehabilitation field.Surrogate endpoints are substitutes for target outcomes of interest in randomized controlled trials, such as person-centered outcomes, and are used to improve trial efficiency.Surrogate endpoints are underutilized as primary outcomes and inconsistently reported in rehabilitation randomized controlled trials.Less than 50% of the rehabilitation randomized controlled trials showed compliance with some of the validity items of the CONSORT-surrogate checklists.Rehabilitation professionals should critically assess trials using surrogate endpoints, ensure their validity in predicting patient-relevant outcomes and consider their limitations when interpreting results.