Retain Patients, Maintain the Statistical Power of Your Study

Posted by Paddy Wall on Jan 21, 2019 10:58:41 AM

In all clinical trials, the goal is to demonstrate a statistically significant difference between the intervention being tested and the control. And this depends on three things: the size of the effect observed, the number of times the effect is observed, and the variation in the effect across the trial population.

To optimize the chances of seeing a robust effect, you need to give your trial plenty of statistical power. This means carefully planning the number of participants you need in your study, and then ensuring you can recruit and retain them.  

Barriers to Achieving Sufficient Study Power

One of the more obvious barriers to achieving sufficient study power is when you are studying a rare event or disease in a population. This presents unique challenges that have ultimately led to slower progress being made in rarer diseases, and has prompted the International Rare Disease Research Consortium to establish a Task Force on Small Population Clinical Trials (SPCT).

Yet small sample sizes can also occur in trials for common diseases due to recruitment failure. In both scenarios, there is the need to explore alternative ways of designing studies to ensure the best chance of seeing an effect. The SPCT Task Force also recommends that sponsors should evaluate the recruitment strategies used in their trials to build the research knowledge in this area and inform subsequent study designs.

And although the number of participants you can enroll in your study may be influenced by the disease being studied, or the resource available, there are other important ways to maximize your chance of achieving a well-powered study.

A Patient-Centric Approach to Retaining Patients

In both rare and common disease clinical trials, the planned recruitment targets must take into account loss of data due to incomplete follow-up or patient drop-out. But of course, the better option is to avoid losing participants at all – especially if your patient pool is small to start with. That’s why adopting a more patient-centred approach to recruiting and retaining participants is becoming ever more important.

In a patient-centered trial for localized prostate cancer, researchers developed a conceptual model of patient-centred recruitment and retention. It came as no surprise to us that strategies related to trust (e.g., physician involvement), communication (e.g., continued contact during regular clinic visits and calling/emailing assessment), attitude (e.g., emphasizing the altruistic value of research), and expectations (e.g., full disclosure of study requirements, update letters) facilitated successful patient recruitment and retention. We’ve heard similar themes in our patient focus groups.

And while it’s true that patient retention may also be improved by new adaptive trial designs, where clinical trial results can be clearly seen to influence the next treatment decision, this alone may not be enough. To maximize the likelihood that a trial is patient-centered, it has been proposed that trial designs involve informed participants and patient advocates in the study design, and that this is supplemented by an online system that lets participants know about the progress of the trial.

Ongoing Engagement

We’ve often heard that it’s common for patients to want to hear more about the results of trials, but busy investigators often do not have time to provide this information. We also hear the story from the other side too, that study teams can be stifled by the requirement of continuous EC/IRB approval. But engagement doesn’t have to be that time-consuming when you have the right tools. That’s why we wanted to harness technology to develop a platform that makes engagement easier, that enables all the essential components of patient-centered trials to fall into place: trusted information, timely communications, a sense of being part of the greater good and creating clear expectations for patients. We can help you to recruit people. And people mean power.

In Summary

  • Patients provide the power to your study
  • Small and large trials have unique recruitment challenges but some common factors
  • Innovative trial designs offer one way of making trials more patient-centric, but a true patient-centered trial involves participants in study design
  • Ongoing engagement, such as sharing interim results and using data in clinical decisions, can help to retain more patients , ensuring statistical significance in your trial

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Topics: Patient Centricity, Patient Compliance, patient engagement, Clinial trial sites, Rare Diseases