While recruiting people into a trial is the single biggest problem, retaining them throughout the trial’s lifespan is another major issue. Which, in turn, leads to additional recruitment activity being required in order to replace them.

There are multiple reasons that people give for dropping out of a trial. Many of them related to the burden of participation – such as the number and frequency of visits to the research site, the length of time it takes to travel to and from the site, and the overall time commitment involved in ongoing participation. All of which can lead to ‘appointment fatigue’.

Another important factor is the extra stress that patients may feel themselves to be under while taking part in a trial. Which can be especially problematic for the many patients who will already be living with chronic conditions that make their lives difficult in the first place.