BONG Clinical Trial

The BONG trial differs from earlier THC studies by focusing specifically on patients with severe and very severe COPD and substantial breathlessness. The planned sample of 30 patients accounts for a 25-30% dropout rate typical of COPD studies; 20 patients are calculated as statistically sufficient. Primary and secondary outcomes are analysed using mixed-effects linear models following the intention-to-treat principle. A 2-week washout period between treatment arms is included to reduce the risk of carryover effects distorting results. The crossover design allows each patient to serve as their own control, reducing interindividual variability and increasing statistical power compared to a parallel-group design. The BONG study is a single-centre, randomised, double-blinded, placebo-controlled crossover trial conducted in an outpatient clinic in Denmark.