A meta-analysis of acute respiratory distress syndrome (ARDS) randomised controlled trials inclusion criteria conducted by a research team at King’s College London and supported by our NIHR Guy’s and St Thomas’ Biomedical Research Centre recommends a wider framework for ARDS case definition in randomised controlled trials.

Acute respiratory distress syndrome (ARDS) is a life-threatening condition where the lungs are significantly impaired and oxygen supply to the body’s vital organs will be affected. ARDS is most often caused by infections such as pneumonia and flu.

One in 10 patients admitted to critical care units globally have a diagnosis of ARDS. About 1 in 3 patients who develop ARDS will die within 30-days in hospital.

Through an assessment of 150 randomised controlled trials involving ARDS patients, the researchers examined how patients were selected into these clinical trials by systematically looking at who were included, why patients were excluded and whether exclusions were strongly or poorly justified.

The inclusion criteria were based on the standardised ARDS definition.

In contrast, there were many poorly justified exclusion criteria in randomised controlled trials with examples such as pregnancy related and younger or older patients.

The study proposes a standardised and simplified exclusion criteria structure for evaluation in future randomised clinical trials to enable inclusion of these under-served groups into clinical research. The authors consider that this will contribute towards the INCLUDE Study discussions for critically ill patients. The ‘INCLUDE project’ aims to improve the inclusion of under-served groups into clinical research.

Dr Rohit Saha, who is the lead author of the paper and a PhD student in the Shankar-Hari translational research group within King’s College London’s School of Immunology and Microbial Sciences student said: “Our research team set out to find out why the same medical condition has different outcomes in different randomised controlled trials. We found a marked inconsistency in how ARDS patients are selected in randomised controlled trials.”

Professor Manu Shankar-Hari, consultant in intensive care medicine at Guy’s and St Thomas’ and an NIHR Clinician Scientist who supervised this work added: “Our study highlights that ARDS still is a big clinical challenge, with one-in-three patients dying within 30-days. We propose implementable solutions to refining how ARDS patients are selected into clinical trials”.

You can read the full study on the National Library of Medicine website.