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Randomised control trials (RCTs) are a gold standard for research – generally gathering their own data despite the UK’s large, and growing, quantity of routinely collected health data (RCHD). This potentially points to large and expensive duplications of effort. In order to gain insights into the issue, and make recommendations for a way forward, the researchers approached registries to ask how many successful RCHD applications were for RCTs.


A step change is urgently needed so that UK clinical trials can fully harness the power of RCHD to conduct more efficient RCTs. However, there has been little research into the extent to which researchers receive data from registries for use in RCTs. Similarly, little was known about the obstacles limiting its use. Understanding these could point to ways forward.


The researchers, including Prof. Matthew R Sydes (HDR UK associated researcher and Professor of Clinical Trials and Methodology at UCL), asked registries about the number of successful applications they had dealt with to supply data for clinical trials. The work (carried out by a HDR –UK funded researcher at the MRC clinical trials unit at UCL) also identified barriers to the use of RCHD. The findings were published in the journal Trials (by BMC) in May 2020.

Lessons Learnt

Only around 2% of successful applications to those registries were for data for RCTs.

Some 160 trials were identified as successfully accessing RCHD to inform participant data, from 22 UK registries, between 2013 and 2018. Many (47%, 43/91) used it for the primary outcome measure. The researchers estimate this equates to fewer than 5% of RCTs in the UK using RCHD. RCHD use was generally for large trials – commonly those evaluating treatments for cancer or cardiovascular disease.

If the potential of RCHD in RCTs is to be tapped – and a move made towards what Prof Sydes calls a “mixed economy” – then barriers need to be addressed including:

  • The need for clear terminology to describe registry data
  • Lack of awareness of RCHD availability and utility
  • Challenges to data accessibility and retention
  • Quality and timeliness
  • Regulatory validity of RCHD.

Impact and outcomes

This is believed to be the first review to approach registries in this way and the first to assess the use of these data specifically for trial outcome measure assessment. It has helped fill a significant gap in the literature.

It underscores the value of HDR UK initiatives such as the development of the Innovation Gateway, which endeavours to improve and increase health data access.

Insights from the Impact Committee

The HDR UK Impact Committee chose this paper for its excellence, significance, originality and rigour. In exploring issues around clinical trials it is also addressing one of HDR UK’s national priorities.