INTRODUCTION:
Equipoise is usually discussed as an ethical issue in clinical trials. However, it also has practical implications.

BACKGROUND:
Clinical equipoise is usually construed to mean uncertainty or disagreement among the expert clinician community. However, an individual physician's sense of equipoise may vary by location, based on the local standard of care or availability of specific treatment options, and these differences can affect providers' willingness to enroll participants into clinical trials. There are also logistical barriers to enrollment in international trials due to prolonged timelines for approvals by government agencies and ethical review boards.

CASE STUDY:
A multinational clinical trial of bridging strategies for treatment of non-adherent HIV-infected youth, experienced differing perceptions of equipoise due to disparities in availability of treatment options by country. Unfortunately, the countries with most demand for the trial were those where the approval process was most delayed, and the study was closed early due to slow accrual.

DISCUSSION:
When planning multicenter clinical trials, it is important to take into account heterogeneity among research sites and try to anticipate differences in equipoise and logistical factors between sites, in order to plan to address these issues at the design stage.