The culture of designing hepato-biliary randomised trials

Research evidence may assist in identifying the best prevention, diagnostic method, or treatment. At the top of the evidence hierarchy you find the randomised clinical trial with low bias risk and systematic reviews Of Such trials. Over 8,500 articles on hepato-biliary randomised trials have been published in over 1,000 journals. Currently, over 500 articles on hepato-biliary randomised trials are published each year. Designing a randomised clinical trial you have to decide the participants and data to include, the experimental intervention (explanatory or pragmatic), the comparator (placebo or active), the basic design (parallel-group, crossover, factorial, cluster), and goal (superiority, equivalence, or non-inferiority). You also have to secure the internal validity (reliability of the results) of the trial. Internal validity may be jeopardised by random errors. The median number of participants per intervention arm in hepatobiliary trials is only about 23, giving ample room for random errors. Internal validity may be jeopardised by systematic errors or bias. Only 48% of hepato-biliary randomised trials report adequate generation of the allocation sequence, 38% adequate allocation concealment, and 34% adequate 'double blinding'. Randomised trials with adequacy of these components are with low bias risk. Hence, more than 90% of hepato-biliary trials may be biased, overestimating intervention effects. By conducting more multi-centre trials, hepato-biliary investigators can include more participants and improve quality. Further, multi-centre trials have better external validity (generalisability of the results) than single-centre trials.