Intention to Treat

Introduction to Intention to Treat

  • Host: Anthony Croco of Sketchy EBM

  • Topic: Intention to treat in randomized control trials (RCTs)

  • Personal anecdote: Bought candy for Halloween but did not give it out—illustrates having intention but not following through.

Overview of Randomized Control Trials (RCTs)

  • Definition: RCTs involve a randomization process to divide participants into two groups:

    • Experimental/Intervention Group: Receives the treatment being tested.

    • Control Group: Receives a placebo or standard treatment.

  • Objective: To observe the effects of the treatment without bias from group assignment.

Compliance Issues in RCTs

  • Participants may deviate from study protocols:

    • Random reasons (e.g., receiving the wrong intervention).

    • Specific reasons (e.g., participants stop adhering due to side effects).

  • Challenges for researchers on how to deal with non-compliant participants' data.

Data Handling Options

  • Per Protocol: Only includes data from participants compliant with the study protocol.

  • As Treated: Analyzes data based on the group participants actually received, irrespective of randomization.

  • Intention to Treat (ITT): Maintains participants in their originally assigned groups, regardless of compliance or treatment received.

Example Analysis

  • Example with two truths:

    • No difference exists between groups; 75% of participants have good outcomes.

  • Scenario with four participants each in control and experimental groups:

    • Control Group: 3 out of 4 have a good outcome (75%).

    • Experimental Group: 3 out of 4 have a good outcome, with one non-compliant participant.

Analysis Outcomes

  • Per Protocol:

    • Control Group: 75% (3/4 good outcomes).

    • Experimental Group: 100% (3/3 good outcomes).

  • As Treated:

    • Control Group now has 5 participants (including one non-compliant)—3 good outcomes (60%); experimental remains at 100%.

  • Intention to Treat:

    • Both groups remain 75% (3/4 good outcomes).

Another Scenario

  • If the non-compliance participant had a good outcome:

    • Per Protocol: Control remains 75%; Experimental group now 67%.

    • As Treated: Control Group: 80% (4/5 good outcomes); Experimental Group: 67%.

    • Intention to Treat: Maintains both groups at 75% good outcomes.

Importance of Intention to Treat Analysis

  • Minimizes bias from non-compliance and helps better reflect real-world scenarios.

  • CONSORT Diagram: Visual representation of participant data throughout the study.

    • Key for understanding how data was handled in RCTs.

Conclusion

  • Importance of evaluating randomized control trials for intention to treat analysis.

  • Encouragement to draw personal conclusions from the analysis presented.