Relearning an old lesson: stopping trials early
- UKCRC Oxford Respiratory Trials Unit, University of Oxford and Oxford Centre for Respiratory Medicine, Oxford Radcliffe Hospital, Oxford, UK
- Correspondence to Robert J O Davies, Oxford Radcliffe Hospital and Oxford University, Churchill Hospital, Headington, Oxford OX3 7LJ, UK;
A well designed and delivered clinical trial is the main tool to define whether medical interventions ‘work’, and how well. As such, they are potent weapons in the armoury of medical progress—and like all potent weapons need to be used with care.
In this month's Thorax, Koegelenberg et al (see page 857) report the findings of a trial comparing the diagnostic accuracy of closed pleural biopsy (Abrams needle) and cutting needle pleural biopsy after thoracic ultrasound, for the diagnosis of pleural tuberculosis (TB).1 This question is clearly important given the global significance of TB, and the key role of pleural biopsy in the diagnosis and microbiological assessment of its pleural presentations. To date, there are no published studies assessing ultrasound-guided pleural biopsy for the diagnosis of TB-related pleural effusions. This study is a continuation of this group's research programme which has a track record of delivering valuable evidence in the diagnosis of pleural TB, not least their previous study showing that thoracoscopy is superior to closed pleural biopsy in this disease.2
Their studies are conducted in an area with a high prevalence of TB, with all the recruited subjects receiving the compared diagnostic tests, allowing the comparison of diagnostic results. In this new study, all patients underwent both Abrams biopsy and cutting needle biopsy, performed in random order. The design is simple, logical and efficient, with the diagnostic accuracy for TB assessed against accepted ‘gold standards’. Given the biology of pleural TB, which manifests as diffuse pleural involvement, it is reasonable to propose that …