Cost-benefit of outcome adjudication in nine randomised stroke trials

Central adjudication of outcomes is common for randomised trials and should control for differential misclassification. However, few studies have estimated the cost of the adjudication process.

We estimated the cost of adjudicating the primary outcome in nine randomised stroke trials (25,436 participants). The costs included adjudicators’ time, direct payments to adjudicators, and co-ordinating centre costs (e.g. uploading cranial scans and general set-up costs). The number of events corrected after adjudication was our measure of benefit. We calculated cost per corrected event for each trial and in total.

The primary outcome in all nine trials was either stroke or a composite that included stroke. In total, the adjudication process associated with this primary outcome cost in excess of £100,000 for a third of the trials (3/9). Mean cost per event corrected by adjudication was £2295.10 (SD: £1482.42).

Central adjudication is a time-consuming and potentially costly process. These costs need to be considered when designing a trial and should be evaluated alongside the potential benefits adjudication brings to determine whether they outweigh this expense.