Do differences in probability of survival affect study design in ICU?

Excerpt

Despite advances in theoretical knowledge, many large prospective trials of novel therapies in trauma and critical care provide disappointing results. This may, in part, be because the wrong patients are included (i.e. those with very high probability of death) or because the therapy may not affect survival but still improve outcome. The early termination of two recent trials has highlighted two main problems with studies in critically ill patients: firstly, it may not be ethical to recruit patients to these trials unless the subgroups who may benefit can be more clearly defined; secondly large amounts of resources are wasted on failed trials. It is therefore very important to understand the nature of the disease, patient disparity, and the effect of the distribution of the probability of survival when testing hypotheses. …