Cluster randomized trials for pharmacy practice research

Area of Science:

• Health services research
• Pharmacy interventions
• Cluster randomized trials (CRTs)

Background:

• CRTs are increasingly the standard in health services research for interventions.
• They are valuable for studies on behavior, epidemiology, lifestyle, education, and healthcare models.
• The unit of randomization (clusters) can differ from the unit of analysis (individuals).

Purpose of the Study:

• To provide an overview of cluster randomized trials (CRTs) in health services and pharmacy research.
• To discuss the methodology, advantages, limitations, and applications of CRTs.
• To illustrate CRT principles using the Collaboration Among Pharmacists and physicians To Improve Outcomes Now (CAPTION) trial.

Main Methods:

• Sample size and cluster number determination based on between- and within-cluster variability (intraclass correlation coefficient - ICC).
• Stratification before randomization to reduce imbalances.
• Adaptations in participant recruitment and potential lack of blinding for behavioral interventions.

Main Results:

• CRTs are suitable for real-world decision-making and non-therapeutic interventions like practice guideline changes.
• Advantages include avoiding contamination and enhancing generalizability of results.
• The CAPTION trial serves as an example of a large CRT in managing hypertension.

Conclusions:

• CRTs are powerful tools in pharmacy research, offering generalizability and preventing contamination.
• Key considerations include sample size, ICC, stratification, and recruitment strategies.
• Despite limitations like cost and complexity, CRTs provide valuable real-world health outcomes data.