Do NIHR health technology assessment randomised clinical trials perform as well as expected?

Results 125 clinical trials published in the HTA Journal Series met the inclusion. Five trials were reported to have been abandoned and were excluded from analyses. 72% of clinical trials achieved 50% or better of their original recruitment target. 90% of clinical trials recruited their targeted number of centres with 50% recruiting more than the initial number they expected. One third of trials amended the sample size calculation after the trial commenced with more than 80% decreasing the number of participants needed for the trial. Conclusions Reviewing the quality of performance of clinical trials will provide important feedback to research management centres about how realistic clinical trialists need to be about trial set up times and its impact on the time required to recruit participating centres.