Factors associated with refusal to enter a clinical trial: epidural anesthesia is a deterrent to participation

To compare patients who participate in a clinical trial for pain management involving epidural anesthesia to those who refuse and document their reasons for refusing.

Demographic and health history information was collected from 621 female patients who were screened for inclusion in a pain management trial involving epidural anesthesia. Patients who completed the clinical trial (n = 149) were compared to those who consented to provide screening information but did not enter the trial (n = 472).

Sixty-seven percent of women who refused cited unwillingness to have an epidural as the reason for their decision. Non-Caucasians (P < 0.01), patients with no history of mood/anxiety disorders (P < 0.016) or systemic disease (P < 0.02), and patients with certain types of pain (P < 0.02) were more likely to refuse to participate in the clinical trial. A longer duration between recruitment and surgery was also found to be associated with higher participation rates (P < 0.01). A logistic regression equation significantly predicted which patients would participate or refuse (P < 0.0001), indicating that a specific set of health and demographic factors strongly influence the decision to participate in a trial.

The decision to participate in a clinical trial is viewed as a risk/benefit analysis. Factors such as short recruitment to surgery intervals and pre-existing pain, which increase the salience of risks associated with the trial, may result in lower participation rates. Overall, epidural anesthesia is a strong deterrent to participation in a clinical trial.