To map the landscape of decentralised clinical trials (DCTs) by summarising characteristics, methods and reported challenges of published DCTs.

Scoping review, reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) checklist.

Ovid MEDLINE and PubMed were searched through to 21 August 2024.

We included reports of completed DCTs (defined as a trial of an intervention, with a comparison arm, in which some or all trial activities occurred away from the trial centre). All intervention types were included.

A single reviewer extracted data to a structured extraction sheet. Descriptive statistics (frequencies) are reported for study characteristics and the terminology used to describe trial methods. Decentralised methods used were coded separately for each trial stage.

53 papers met inclusion criteria. Most studies (34/53) were conducted in the USA. Mental health (18 studies) and COVID-19 (11 studies) were the predominant research areas. 24 (of 53) studies investigated pharmaceutical interventions, while others examined nutritional interventions, medical devices and behavioural interventions. Recruitment, screening and consent were commonly conducted remotely. A range of methods, including online, in-person and telemedicine, was used to collect outcome measures. Several studies experienced challenges related to participant retention and biased recruitment. Terminology regarding decentralisation was inconsistent across studies.

DCTs are rapidly increasing in use, and commonly cited advantages include reduced costs and reduced participant burden. This review identifies key research areas using DCTs and highlights a need for standardised terminology, comprehensive reporting of methods and limitations, and robust regulatory frameworks. Development of formal ethical and reporting standards is essential to ensure effective and responsible implementation of DCTs in clinical research.