CPRD_COPD Hawthorne Effect Study in Salford

Disease Areas Impacted

Chronic Obstructive Pulmonary Disease (COPD)

Project Overview

The Salford Lung Study is a pragmatic randomised controlled trial (pRCT) to test the effectiveness of a novel medicine compared with standard of care among patients with Chronic Obstructive Pulmonary Disease (COPD). A pragmatic trial tests the effectiveness of the drugs in everyday clinical practice, as opposed to under strict clinical trial conditions. It is the first ever pre authorisation pragmatic randomised controlled trial. However, people often act differently when they are aware of being under surveillance (this applies to both patients and clinicians) – known as the Hawthorne Effect. The aim of this study was to compare the patients in the standard of care arm of the Salford Lung Study with other COPD patients in primary care. Then the researchers looked at whether the results from the trial are indeed applicable to everyday clinical practice.

Data Source

A combination of an observational cohort of COPD patients from the Clinical Practice Research Datalink (CPRD) linked with Hospital Episode Statistics (HES) and Office for National Statistics (ONS) data, and trial data from the control arm of the Salford Lung Study (SLS).

Methodology

The researchers compared baseline characteristics (age, social economic status, co-morbidities, etc) of the SLS control arm with the CPRD cohort to place the members of the SLS in a wider context. They then created models that compare the rate of COPD exacerbations in the two groups to see if the rates of COPD exacerbation in the SLS are unusual. They considered the natural variation in the CPRD cohort which includes patients from all over the UK and assessing whether the SLS patients fit within this.

Benefits

It is rare for the effectiveness of drugs in routine clinical practice to be known pre (or even post) authorisation. The SLS aimed to uncover exactly this. It is therefore important to assess this key aspect of the design to provide more evidence to clinicians who will potentially be prescribing the drugs, ultimately leading to better care for COPD patients.

Intended Outcomes

The outcome was to assess whether there was a presence of the Hawthorne effect. The findings will be presented alongside the trial results to aid their interpretation.

Findings

The SLS itself had positive findings. It found that in patients with COPD and a history of exacerbations, a once-daily treatment regimen of combined fluticasone furoate and vilanterol was associated with a lower rate of exacerbations than usual care, without a greater risk of serious adverse events. Overall the project showed that it was feasible to conduct trials in unselected populations without strong concerns about Hawthorne effect.

Publications from these findings:

https://onlinelibrary.wiley.com/doi/full/10.1002/pds.4883

https://bmjopenrespres.bmj.com/content/5/1/e000339

Hopes for the future

Overall the work (our study plus the main SLS) demonstrates that performing clinical trials with mimimal exclusion criteria alongside routine care is feasible and provides results that are generalisable. Particularly with an ageing population and increasing numbers of people living with multiple conditions, it is important to conduct trials in unselected rather than ideal populations. This will allow better knowledge of how treatments and interventions work in the population.

Funding

GlaxoSmithKline

Researchers Involved

Dr Matthew Sperrin, Prof Tjeerd Van Staa, Alexander Pate, Michael Barrowman

Additional Information

The study is registered as an EU-PAS study and holds the ENCePP study seal. This represents external recognition of high standards throughout the research process – see www.encepp.eu