What is the criterion for patients to be considered in the per-protocol population?

The criterion for patients to be considered in the per-protocol population is based on their adherence to the trial protocol. Specifically, this population typically includes all patients who did not have significant protocol violations. This means that these patients followed the treatment regimen and other specified procedures sufficiently to allow for a valid assessment of the treatment’s efficacy.

This approach is important because the per-protocol analysis aims to evaluate the treatment effect among those participants who were compliant with the study regimen, which provides a clearer picture of how the treatment would perform under ideal circumstances. Protocol violations could include serious deviations like not adhering to the assigned treatment, missing several doses, or failing to attend required assessments. By focusing on patients who adhered closely to the protocol, researchers can better estimate the treatment effect without the variability introduced by noncompliance.

The other options do not accurately define the criteria for inclusion in the per-protocol population. For instance, simply following the protocol strictly would exclude patients who might have minor deviations but still provide useful data. Reporting side effects or completing follow-up appointments does not provide sufficient context about their adherence to the treatment regimen specified in the protocol. Thus, adherence to the protocol without significant violations is the key criterion.