In a clinical trial using a Cox proportional hazards model, what type of analysis is performed?

In a clinical trial utilizing a Cox proportional hazards model, the analysis performed is primarily focused on time-to-event data, often referred to as survival analysis. The Cox model evaluates the relationship between the survival time of patients and one or more predictor variables, allowing researchers to assess the effect of treatments or interventions while controlling for various covariates.

Intention-to-treat analysis is an essential principle in clinical trials, including those employing the Cox model. This approach involves including all participants in the groups to which they were randomly assigned, regardless of whether they completed the intervention according to the protocol. By doing so, the intention-to-treat analysis preserves the randomization process and helps maintain the integrity of the comparison between treatment and control groups, reducing bias and providing a more credible estimate of treatment effect.

While other types of analysis like post hoc analysis, metaregression, and subgroup analysis have their specific purposes, they do not primarily focus on the preservation of randomization and the initial treatment assignment as intention-to-treat analysis does. Therefore, in the context of a clinical trial using a Cox proportional hazards model, intention-to-treat analysis is the method that emphasizes maintaining the integrity of the original study design and provides robust results regarding treatment effectiveness.