Intention-To-Treat (ITT) Analysis

An Intention-To-Treat (ITT) Analysis is a Clinical Analysis Method that evaluates clinical trial results based on initial pre-assigned medical treatment and not on the one actually received.

• AKA: Intention-to-Treat.
• Example(s):
  • …
• Counter-Example(s):
  • Per-Protocol Analysis.
• See: Clinical Trial Arm, Randomized Controlled Trial, Clinical Trial Participant Allocation Task, Crossover Clinical Trial, Multi-Arm Clinical Trial, Placebo-Controlled Clinical Trial, Exploratory Clinical Trial, Confirmatory Clinical Trial.

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References

2022a

• (Wikipedia, 2022a) ⇒ https://en.wikipedia.org/wiki/Intention-to-treat_analysis Retrieved:2022-3-19.
  • In medicine an intention-to-treat (ITT) analysis of the results of an experiment is based on the initial treatment assignment and not on the treatment eventually received. ITT analysis is intended to avoid various misleading artifacts that can arise in intervention research such as non-random attrition of participants from the study or crossover. ITT is also simpler than other forms of study design and analysis, because it does not require observation of compliance status for units assigned to different treatments or incorporation of compliance into the analysis. Although ITT analysis is widely employed in published clinical trials, it can be incorrectly described and there are some issues with its application. Furthermore, there is no consensus on how to carry out an ITT analysis in the presence of missing outcome data.

2022b

• (Wikipedia, 2022b) ⇒ https://en.wikipedia.org/wiki/Glossary_of_clinical_research#I Retrieved:2022-3-19.
  • QUOTE: Intent to treat
    • Analysis of clinical trial results that includes all data from participants in the groups to which they were randomized even if they never received the treatment. (NLM)
    • The principle that asserts that the effect of a treatment policy can be best assessed by evaluating on the basis of the intention to treat a subject (i.e. the planned treatment regimen) rather than the actual treatment given. It has the consequence that subjects allocated to a treatment group should be followed up, assessed and analysed as members of that group irrespective of their compliance to the planned course of treatment. (ICH E9)

2017

• (McCoy, 2017) ⇒ C. Eric McCoy (2017). "Understanding the Intention-to-treat Principle in Randomized Controlled Trials". In: Western Journal of Emergency Medicine, 18(6), 1075.
  • QUOTE: Intention-to-treat analysis is a method for analyzing results in a prospective randomized study where all participants who are randomized are included in the statistical analysis and analyzed according to the group they were originally assigned, regardless of what treatment (if any) they received. This method allows the investigator (or consumer of the medical literature) to draw accurate (unbiased) conclusions regarding the effectiveness of an intervention. This method preserves the benefits of randomization, which cannot be assumed when using other methods of analysis.

2011

• (Gupta, 2011) ⇒ Sandeep K. Gupta (2011). "Intention-to-treat concept: A review". In: Perspectives in clinical research, 2(3), 109.
  • QUOTE: According to Fisher et al. (1990), the ITT analysis includes all randomized patients in the groups to which they were randomly assigned, regardless of their adherence with the entry criteria, regardless of the treatment they actually received, and regardless of subsequent withdrawal from treatment or deviation from the protocol.

    In other words, ITT analysis includes every subject who is randomized according to randomized treatment assignment. It ignores noncompliance, protocol deviations, withdrawal, and anything that happens after randomization. ITT analysis is usually described as “once randomized, always analyzed”.

     ITT analysis avoids overoptimistic estimates of the efficacy of an intervention resulting from the removal of non-compliers by accepting that noncompliance and protocol deviations are likely to occur in actual clinical practice.

2002

• (Soares & Carneiro, 2002) ⇒ Isabel Soares, and Antonio Vaz Carneiro (2002). "Intention-to-treat analysis in clinical trials: principles and practical importance.". In: Revista portuguesa de cardiologia: orgao oficial da Sociedade Portuguesa de Cardiologia= Portuguese journal of cardiology: an official journal of the Portuguese Society of Cardiology, 21(10), 1191-1198.
  • QUOTE: Intention-to-treat analysis is a technique used in randomized controlled trials (RCTs), where patients are compared--in terms of their final results--within the groups to which they were initially randomized, independently of receiving the allocated treatment, having dropped out of the study or having violated the initial protocol (for whatever reason). In other words, it constitutes an analysis of the results based on the treatment arm to which the patients belong due to the initial random allocation, and not on the treatment actually received (active or placebo). Intention-to-treat analysis permits the pragmatic evaluation of the benefit of a treatment change, and not the potential benefit in patients getting the pre-planned allocated treatment only. Full application of the intention-to-treat principle is only possible in those circumstances where all results from all patients are available.

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