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The importance of statistical analysis in clinical trials

If you are wondering why clinical trials need a statistical analysis… If you want to learn about the role of people involved in data analysis and protocol elaboration… Read on!

By Mercedes Ovejero Bruna

Análisis de datos

Expert in statistical analysis of clinical trials

According to the ICH (International Council for Harmonization) guidelines, issued by the European Medicines Agency (section E9), clinical trial statisticians must be involved from the beginning of the protocol elaboration. Their knowledge should contribute to the design of the clinical trial, the sample size calculation, the design, and the review of the Case Report Form (CRF), and the planning of the statistical analysis as stated by the clinical trial objectives.

Moreover, a clinical trial statistician oversees making the Statistical Analysis Plan, a document that describes the purpose, variables and the details of the statistical analysis that will be used. Therefore, the participation of statisticians in clinical research and clinical trials follows the Good Clinical Practice guidelines and is essential for the clinical trial to be conducted in an efficient and compliant way.

What can we learn from statistical analysis in a clinical trial?

As a rule, thanks to statistical analysis we can answer questions such as:

  • What are the characteristics of the patients included in a clinical trial?
  • Is the treatment safe?
  • Is the treatment effective?
  • Is the treatment more effective than placebo or other available treatments?
  • Does the treatment improve patient’s quality of life?


Composición Merche Ovejero artículo análisis estadístico


Six key elements of data analytics in clinical trials

  1. Data analysis must be based on the protocol and the Statistical Analysis Plan.
  2. The phase of the clinical trial is crucial when it comes to choose the type of statistical analysis to perform. For example, Phase I clinical trials usually have a smaller number of patients. They require a thorough safety analysis, to be complemented with both individual and group patient’s initial efficacy indicators.
  3. To delimitate the group of patients to be analyzed, we need to elaborate the patients’ flow chart, as well as defining the study populations. This way we will get more accurate analysis.
  4. Statistical analysis must focus on efficacy and safety, which are the main areas of any clinical trial. Currently more and more studies are including quality of life assessments as well. It is becoming increasingly relevant to prove not only that those treatments are effective and safe, but that they also improve patients’ quality of life.
  5. It is important that the results are statistically significant, but the key to know whether the impact is relevant for patients’ health is to consider the magnitude of results by computing the effect size.
  6. Fully understanding the results of a statistical analysis is essential for clinical research as it allows to understand the scope and magnitude of the treatments’ impact on health, safety, and quality of life of patients.

As stated, statistical analysis is critical for clinical trials! It allows us to connect the protocol objectives to the analysis described in the Statistical Analysis Plan, so we can quantify the effect of experimental treatments. Conclusions on efficacy, safety and quality of life can be drawn thanks to it.

Statistical analysis is, therefore, a key role within a clinical trial, as it facilitates the design of subsequent studies, the compliance with good clinical practice, and regulatory approval.


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