Factors affecting patient participation in orthopaedic trials comparing surgery to non-surgical interventions

Randomized controlled trials (RCTs) are considered the most robust research design to determine the effectiveness of interventions. RCTs comparing surgery to non-surgical alternatives are particularly difficult to perform, partly due to difficulties with recruitment. Low recruitment rates can limit the internal and external validity of a trial thus understanding their causes may be important for avoiding protracted recruitment periods. This study aimed to report patient factors that influenced participation in a trial comparing surgery to a non-surgical treatment approach.

This study was a cross-sectional study nested within CROSSBAT (Combined Randomized and Observational Study of Surgery For Type B Ankle Fracture Treatment). Eligible participants willing to be randomized were randomized while those who declined randomization were offered participation in an observational cohort. Participants from both groups (randomized and observational) were asked to indicate their level of agreement on a 100 mm line with statements concerning reasons for acceptance or rejection of randomization. A subset were asked to state the primary reason for agreeing to participate or not in the trial.

The nested study included 312 participants; 113 who accepted and 199 who declined randomization. Participants unwilling to be randomized (those in the observational arm of the study) predominantly received a non-surgical intervention. They were significantly more worried about receiving treatment by chance (55 mm vs. 33 mm; p < 0.0001) and had a significantly higher preference for one particular treatment (less equipoise) (82 mm vs 43 mm; p < 0.0001) compared to participants willing to be randomized. Influence from clinicians and risk avoidance were primary influences of participation. Participants' responses regarding protocol burden, study follow-up requirements and altruism did not significantly differ between groups.

Patient non-participation in an RCT comparing surgery to no surgery is related to concern about receiving a treatment through chance and the presence of a strong preference for a particular treatment, particularly a non-surgical one. To avoid protracted recruitment periods, investigators can increase the number of study sites and ensure personnel involved have equipoise and are trained to provide a balanced view of both treatment arms.